International Commission on Zoological Nomenclature:
OPINIONS and DIRECTIONS

taxa names:

Cy

cyanea Fabricius 1775 [originally in Buprestis], Systema Entomologiae, sistens insectorum classes, ordines, genera, species ..., p. 223 (specific name of the type species of Phaenops Dejean 1833) (Insecta, Coleoptera). Opinion 1826  

cyanea Fabricius 1798 [originally in Lema], Suppl. Entomol. syst.: 92 (specific name of the type species of Lema Fabricius 1798) (Insecta, Coleoptera). Opinion 908 

cyanea Linnaeus 1758 [originally in Loxia], Systema Naturae, Ed. 10, vol. 1, p. 174 (suppressed under the plenary power for the purposes of both the Principle of Priority and the Principle of Homonymy). Opinion 1126

cyanea Müller [1776] [originally in Muscicapa], Linné vollständ. Natursyst., Suppl.: 170 (Aves). Opinion 415

cyanea Vieillot 1818 [originally in Muscicapa], Nouv. Dict. Hist. nat. (ed. 2), 21: 447 (suppressed under the plenary power for the purposes of both the Principle of Priority and the Principle of Homonymy). Opinion 415 

cyanea Hume 1877 [originally in Muscitrea], Stray Feathers, 5: 101 (conserved under the plenary power) (Aves). Opinion 415 

cyanea Cramer [1775] [originally in Papilio], De Uitlandsche Kapellen voorkommende in de drie Waerelddeelen Asia, Africa en America, vol. 1, p. 120 (specific name of the type species of Pepliphorus Hübner [1819]) (Insecta, Lepidoptera). Opinion 1773

cyanea Linnaeus 1766 [originally in Tanagra], Systema Naturae, Ed. 12, vol. 1, part 1, p. 315 (Aves). Opinion 1126 

cyaneofulvus Houttuyn [1787] [originally in Cerambyx], Anim. Mus. Houtt. Index: 72 (included in a work suppressed under the plenary power for nomenclatural purposes). Opinion 380  

cyaneopunctatus Houttuyn [1787] [originally in Cerambyx], Anim. Mus. Houtt. Index: 72 (included in a work suppressed under the plenary power for nomenclatural purposes). Opinion 380  

cyanipes Fabricius 1787 [originally in Buprestis], Mantissa insectorum ..., vol. 1, p. 178 (Insecta, Coleoptera). Opinion 2008

cyanipes Say 1823 [originally in Buprestis], Journal of the Academy of Natural Sciences of Philadelphia, 3: 164, ruled under the plenary power to be treated as not invalid by reason of having been originally published as a junior primary homonym of Buprestis cyanipes Fabricius 1787 (Insecta, Coleoptera). Opinion 2008

cyanoleucus Latham 1801 [originally in Corvus], Supplementum Indicis Ornithologici, sive Systematis Ornithologiae, p. 25 (Aves). Opinion 2240

cyathiformis Spencer 1878 [originally in Calyptograpsus (sic)], Canadian Naturalist, 8: 459 (specific name of the type species of Calyptograptus Spencer 1878) (Graptolithina). Opinion 650 

Cyathocrinites Miller 1821, Nat. Hist. Crinoidea: 85 (gender: masculine) (type species, by designation under the plenary power: Cyathocrinites planus Miller 1821, Nat. Hist. Crinoidea: 85) (Crinoidea). Opinion 917

Cyatholithus Huxley 1868, Trans. roy. Micros. Soc. (n.s.), 15: 206 (suppressed under the plenary power for the purposes of the Principle of Priority but not for those of the Principle of Homonymy). Opinion 805  

Cyathostomum Molin 1861, Memorie del Reale Istituto Veneto di Scienze, Lettere ed Arti, 9: 453 (gender: neuter) (type species, by monotypy: Strongylus tetracanthus Mehlis 1831) (Nematoda). Opinion 1972  

CYCLADIDAE (as CYCLADIA) Rafinesque 1820, Ann. gén. Sci. phys., 5: 318 (see also Prime, 1851, Proc. Boston Soc. nat. Hist.: 155) (type genus: Cyclas Lamarck [1798]) (invalid because the name of the type genus is a junior objective synonym rejected before 1961). Direction 117

Cycladigenus [Renier] [1807], [Tav. serv. Class. Conn. Anim.]: Tav. VII (included in a work rejected for nomenclatural purposes). Opinion 427

Cyclas Lamarck [1798], Tabl. encycl. trois règnes de la nature: pls. 301, 302 (a junior objective synonym of Sphaerium Scopoli 1777). Direction 117

Cyclaxyra Broun 1893, Manual of New Zealand Coleoptera, part 5, p. 1076 (gender: feminine) (type species, by monotypy: Cyclomorpha politula Broun 1881) (Insecta, Coleoptera). Opinion 1472 

Cycloceras M’Coy, 1844, A synopsis of the characters of the Carboniferous Limestone fossils of Ireland, p. 6 (gender: neuter) (type species, designated under the plenary power: Cycloceras laevigatum M’Coy, 1844) (Cephalopoda, Nautiloidea). Opinion 1720

Cycloderes Sahlberg 1823, Periculi entomographici ..., pp. 21, 83 (gender: masculine) (type species, by monotypy: Cycloderes catarractus Sahlberg 1823) (Insecta, Coleoptera). Opinion 1440 

Cyclodinus Mulsant & Rey 1866 (Coleoptera). ICZN 2016: Opinion 2377

Cyclodius Dana 1851, Amer. J. Sci., (2)12: 126 (gender: masculine) (type species, by designation by Rathbun, 1922 (Smithson. misc. Coll., 73 (No. 1): 26): Cyclodius ornatus Dana 1852, Proc. Acad. nat. Sci. Philadelphia, 6: 80) (Crustacea, Decapoda). Opinion 73, Direction 37  

Cyclogyra Wood 1842, Ann. Mag. nat. Hist., (1)9: 458 (suppressed under the plenary power for the purposes of the Principle of Priority but not for those of the Principle of Homonymy). Opinion 1114

Cyclope Risso 1826, Hist. nat. princip. Prod. Europ. mérid., 4: 170, 271 (gender: feminine) (type species, by designation by Keen, 1964 (Bull. zool. Nomencl., 21: 303): Cyclope neritoidea Risso 1826, Hist. nat. princip. Prod. Europ. mérid., 4: 170, 271, valid name: Buccinum neriteum Linnaeus 1758) (Gastropoda). Opinion 793

Cyclopterus Linnaeus 1758, Systema Naturae, Ed. 10, vol. 1, p. 260 (gender: masculine) (type species, by Linnaean tautonymy: Cyclopterus lumpus Linnaeus 1758, Systema Naturae, Ed. 10, vol. 1, p. 260) (Osteichthyes). Opinion 77, Direction 56

Cyclopterus Marseul 1872, Abeille, 10: 30 (a junior homonym of Cyclopterus Linnaeus 1758). Direction 56

Cyclosalpa Blainville 1827, Dict. Sci. nat., 47: 108 (gender: feminine) (type species, by designation by Metcalfe, 1918 (Bull. U.S. nat. Mus., 100, 2(2): 9): Salpa pinnata Forsskål 1775, Descr. Anim.: 112) (Urochordata). Opinion 888

Cyclosiphon Ehrenberg 1856, Abh. K.-preuss. Akad. Wiss., Berlin, 1855 (Phys.): 168 (suppressed under the plenary power for the purposes of the Principle of Priority but not for those of the Principle of Homonymy in Opinion 127). Direction 76

Cyclostomigenus [Renier] [1807], [Tav. serv. Class. Conn. Anim.]: Tav. VIII (included in a work rejected for nomenclatural purposes). Opinion 427

cydippe [originally in Papilio], all uses of, subsequent to Linnaeus, 1761, and prior to cydippe Linnaeus 1767 [originally in Papilio] (suppressed under the plenary power for the purposes of both the Principle of Priority and the Principle of Homonymy). Opinion 501  

cydippe Linnaeus 1761 [originally in Papilio], Fauna svec. (ed. 2): 281 (suppressed under the plenary power for the purposes of the Principle of Priority but not for those of the Principle of Homonymy). Opinion 501 

cydippe Linnaeus 1767 [originally in Papilio], Systema Naturae, Ed. 12, vol. 1, part 2, p. 776 (Insecta, Lepidoptera). Opinion 501

cygneus Linnaeus 1758 [originally in Mytilus], Systema Naturae, Ed. 10, vol. 1, p. 706, as defined by the lectotype (shell inscribed ‘218’ and ‘cygneus’ in Linnaeus’s handwriting in the collection of the Linnean Society of London) designated by Bloomer, 1938, Journal of Conchology, 21: 39) (specific name of the type species of Anodonta Lamarck 1799) (Bivalvia). Opinion 336, Opinion 1651  

Cylichna Lovén 1846, Öfvers. K. Vet. Ak. Förh., III(5): 142 (gender: feminine) (type species, bydesignation by Pilsbry, 1893 (in Tryon, Man. Conch., 15: 287): Bulla cylindracea Pennant 1777, Brit. Zool. (ed. 4), iv: 100) (Gastropoda). Opinion 1030 

Cylichnostomum Looss 1901, Records of the Egyptian Government School of Medicine, Cairo, 1: 36, 86 (a junior objective synonym of Cyathostomum Molin 1861) (Nematoda). Opinion 1972  

Cylicostomum Railliet 1901, Echo Vétérinaire (Liége), 30(1): 40 (a junior objective synonym of Cyathostomum Molin 1861) (Nematoda). Opinion 1972 

cylindracea Pennant 1777 [originally in Bulla], Brit. Zool. (ed. 4), IV: 100 (specific name of the type species of Cylichna Lovén 1846) (Gastropoda). Opinion 1030  

cylindraceus da Costa 1778 [originally in Turbo], Hist. nat. Testac. Brit.: 89 (valid name at the date of Opinion 335 of the type species Lauria Gray 1840) (Gastropoda). Opinion 335

cylindraria Pallas 1766 [originally in Nereis], Misc. zoologica: 117 (suppressed under the plenary power for the purposes of the Principle of Priority but not for those of the Principle of Homonymy). Opinion 1225

Cylindrella Swainson 1840, A Treatise on Malacology, in Lardner’s Cabinet Cyclopaedia, London: 135 (a nomen nudum). Opinion 1030  

Cylindrella Swainson 1840, A Treatise on Malacology, in Lardner’s Cabinet Cyclopaedia, London: 311 (suppressed under the plenary power for the purposes of both the Principle of Priority and the Principle of Homonymy). Opinion 1030

Cylindrella Swainson 1840, A Treatise on Malacology, in Lardner’s Cabinet Cyclopaedia, London: 326 (suppressed under the plenary power for the purposes of both the Principle of Priority and the Principle of Homonymy). Opinion 1030

cylindrica Fabriciu, 1775 [originally in Buprestis], Systema entomologia, p. 220 (specific name of the type species of Acmaeodera Eschscholtz 1829) (Insecta, Coleoptera). Opinion 2100 

cylindrica Férussac 1807 [originally in Vertigo], Essai Méth. conchyl.: 52 (Gastropoda). Opinion 336

cylindricum Say 1818 [originally in Pinnotheres], J. Acad. nat. Sci. Philadelphia, 1(2): 452 (specific name of the type species of Pinnixa White 1846) (Crustacea, Decapoda). Direction 36  

cylindricus Menke 1828 [originally in Bulimus] (Gastropoda). ICZN 2015: Opinion 2363

cylindricus Müller 1776 [originally in Ptilinus], Zoologiae Danicae prodromus, p. 81 (suppressed under the plenary power for the purposes of both the Principle of Priority and the Principle of Homonymy) (Insecta, Coleoptera). Opinion 1754  

cylindricus Gmelin, 1791 [originally in Trochus], Caroli a Linné Systema Naturae, Ed. 13, vol. 1, part 6 (Vermes), p. 3572. Lipsiae (senior synonym of Solarium herberti Deshayes, 1830, specific name of the type species of Heliacus d’Orbigny 1842) (Gastropoda). Opinion 2185  

Cylindrogaster Lioy 1864, Atti dell’Istituto Veneto di Scienze, Lettere ed Arti, (3)9(2): 1327 (a junior objective synonym of Sicus Scopoli 1763) (Insecta, Diptera). Opinion 1870 

Cylindrus Batsch 1789 (Gastropoda). ICZN 2018: Opinion 2422

Cylindrus Deshayes 1824 (Gastropoda). ICZN 2018: Opinion 2422

cylindrus Fabricius, 1777 [originally in Cancer], Gen. Ins.: 248 (specific name of the type species of Ixa Leach, 1815) (Crustacea, Decapoda). Direction 36  

Cyllopisalia Pace 1982, Bollettino della Società entomologica Italiana, 114: 40 (gender: feminine) (type species, by original designation of the replaced nominal genus Parapisalia Scheerpeltz, 1966: Homalota difformis Mulsant & Rey 1853) (Insecta, Coleoptera). Opinion 2113

Cymatia Flor 1860, Die Rhynchoten Livlands, vol. 1, p. 799 (gender: feminine) (type species, by subsequent designation by Kirkaldy, 1898, Entomologist, 31: 252: Sigara coleoptrata Fabricius [1777]) (Insecta, Heteroptera). Opinion 1650, Opinion 1794

CYMATIAINAE Walton in Hutchinson 1940, Transactions of the Connecticut Academy of Arts and Sciences, 33: 344 (type genus: Cymatia Flor, 1860), spelling emended from CYMATIINAE by the ruling under the plenary power that for the purposes of Article 29 of the Code the stem of the generic name Cymatia Flor 1860 is CYMATIA- (Insecta, Heteroptera). Opinion 1650

CYMATIINAE Iredale 1913 (1854), The Nautilus, 27: 56 (type genus: Cymatium [Röding] 1798) (Gastropoda). Opinion 1650  

CYMATIINAE Walton in Hutchinson 1940, Transactions of the Connecticut Academy of Arts and Sciences, 33: 344, spelling emended to CYMATIAINAE following the ruling under the plenary power that for the purposes of Article 29 of the Code the stem of the generic name Cymatia Flor 1860 is CYMATIA- (Insecta, Heteroptera). Opinion 1650  

Cymatium [Röding] 1798, Museum Boltenianum, sive catalogus cimeliorum e tribus regnis naturae quae olim collegerat joa. Fried. Bolten ... pars secunda, p. 129 (gender: neuter) (type species, by subsequent designation by Dall, 1904, Smithsonian Miscellaneous Collections, 47: 133: Murex femorale Linnaeus 1758) (Gastropoda). Opinion 1650  

Cymbium Bertrand 1763, Dict. Univ. Foss. Propres Foss. Accid., 1: 143 (included in a work rejected for nomenclatural purposes). Opinion 592

Cymo de Haan [1833], in Siebold, Fauna japon., (Crust.): 5, 22 (gender: masculine) (type species, by monotypy: Pilumnus andreossyi Audouin [1826], in Savigny, Descr. Egypte, 1(4) (expl. pls. Crust.): 86) (Crustacea, Decapoda). Opinion 73, Direction 37  

cymodoce d’Orbigny 1850 [originally in Ammonites], Pal. franç., Terr. jurass., 1: 534, pl. 202, figs. 3, 4 (nec figs. 1, 2) as interpreted by the lectotype designated by Tornquist, 1896 (Abh. schweiz. pal. Ges., 23: 8) (Cephalopoda). Opinion 426 

cymodoce Herbst 1801 [originally in Cancer], Versuch einer Naturgeschichte der Krabben und Krebse, vol. 3, part 2, p. 22 (senior subjective synonym of the specific name of Trapezia dentifrons Latreille, 1828, the type species of Trapezia Latreille 1828) (Crustacea, Decapoda). Opinion 1614

Cymonomus Milne Edwards 1880, Bull. Mus. comp. Zool., 8(1): 26 (gender: masculine) (type species, by monotypy: Cymonomus quadratus Milne Edwards 1880, Bull. Mus. comp. Zool., 8(1): 26) (Crustacea, Decapoda). Opinion 712

Cymopolia Roux 1830, Crust. Médit., (5): pl. 21 (a junior homonym of Cymopolia Lamouroux, 1816). Opinion 712

CYMOPOLIIDAE (correction of CYMOPOLIDAE) Dana 1854, Amer. J. Sci., (2)18: 9 (type genus: Cymopolia Roux 1830) (invalid because the name of the type genus is a junior homonym). Opinion 712

Cynocephalus Boddaert 1768, Dierkundig Mengelwerk, 2: 8 (gender: masculine) (type species, by monotypy: Lemur volans Linnaeus 1758, Systema Naturae, Ed. 10, vol. 1, p. 30) (Mammalia). Opinion 1077  

Cynochampsa Owen 1859, Quart. J. geol. Soc. London (1) Proc. geol. Soc. London, 16: 61 (suppressed under the plenary power for the purposes of the Principle of Priority but not for those of the Principle of Homonymy). Opinion 1324

Cynodon Cuvier 1829, Le règne animal distribué d’après son organisation, pour servir de base à l’histoire naturelle des animaux et d’introduction à l’anatomie comparée, Ed. 2, vol. 2, p. 312 and all uses of the name Cynodon prior to the publication of Cynodon Spix in Spix & Agassiz 1829 (suppressed for the purposes of both the Principle of Priority and the Principle of Homonymy) (Osteichthyes). Opinion 2012

Cynodon Spix in Spix & Agassiz 1829, Selecta genera et species piscium quos in itinere per Brasiliam ... Collegit et pingendos curavit Dr. J.B. de Spix ... Digessit, descripsit et observationibus anatomicis illustravit Dr. L. Agassiz, pl. 26 (gender: masculine) (type species, by designation under the plenary power: Cynodon gibbus Spix & Agassiz 1829), ruled under the plenary power not to be given priority over the name Rhaphiodon Agassiz in Spix & Agassiz 1829 whenever the two names are considered to be synonyms (Osteichthyes). Opinion 2012  

Cynogale Gray [1837], Proc. zool. Soc. London, 4: 88 (gender: feminine) (type species, by monotypy: Cynogale bennettii Gray [1837], Proc. zool. Soc. London, 4: 88) (Mammalia). Opinion 384

Cynogale Lund 1842, K. Danske Vid. Selsk. Afh., 9: 203 (a junior homonym of Cynogale Gray [1837]). Opinion 384  

CYNOGALINA Gray [1865], Proc. zool. Soc. London, 1864: 507, 521 (type genus: Cynogale Gray [1837]) (an incorrect original spelling for CYNOGALINAE Gray [1865]). Direction 53 

CYNOGALINAE (correction by Gill 1872 (Smithson. misc. Coll., 230: 4, 62) of CYNOGALINA) Gray [1865], Proc. zool. Soc. London, 1864: 507, 521 (type genus: Cynogale Gray [1837]) (Mammalia). Direction 53  

Cynthia Fabricius 1807, Mag. f. Insektenk. (Illiger), 6: 281 (gender: feminine) (type species, by designation by Westwood [1840] (Introd. mod. Class. Ins., 2, Syn. Gen. brit. Ins.: 87): Papilio cardui Linnaeus 1758, Systema Naturae, Ed. 10, vol. 1, p. 475) by direction under the plenary power, not to be used in preference to Vanessa Fabricius 1807, but available for use by those who consider that the type species of this genus is not congeneric with Papilio atalanta Linnaeus 1758, the type species of Vanessa Fabricius 1807 (Insecta, Lepidoptera). Direction 4  

Cyon Agassiz 1846, Nomencl. zool. Index Univ.: 113 (an unjustified emendation of Cuon Hodgson, 1838). Opinion 384

cyparissa Cramer [1775] [originally in Papilio], Uitlandsche Kapellen ..., vol. 1, part 4, p. 63, pl. 39, figs. D, E (specific name of the type species of Euphaedra Hübner [1819]) (Insecta, Lepidoptera). Opinion 1380 

Cyphaspis Burmeister 1843, Organisation und Ubersicht Trilobiten, p. 103 (gender: feminine) (type species, by designation under the plenary power: Phacops ceratophthalmus Goldfuss 1843) (Trilobita). Opinion 1434

Cyphodeirus Nicolet [1842], Neue Denkschr. allgem. schweiz. Ges., 6: 63 (an incorrect original spelling for Cyphoderus Nicolet [1842]). Opinion 291 

Cyphoderus (emendation of Cyphodeirus) Nicolet [1842], Neue Denkschr. allgem. schweiz. Ges., 6: 63 (gender: masculine) (type species, by designation by Börner, 1903 (SitzBer. Ges. naturf. Freunde Berlin, 1903: 180): Cyphodeirus [sic] albinus Nicolet [1842], Neue Denkschr. allgem. schweiz. Ges., 6: 67) (Insecta, Collembola). Opinion 291

Cyphogastra Deyrolle 1864, Annales de la Société Entomologique de Belgique, 8: 36 (gender: feminine) (type species, by subsequent designation by Bellamy, 1998, Deutsche Entomologische Zeitschrift, 45(1): 10: Buprestis foveicollis Boisduval 1835) (Insecta, Coleoptera). Opinion 2008

Cyphonota Dejean 1833, Catalogue des Coléoptères de la collection de M. le Comte Dejean, Livraison 1, p. 79 (suppressed for the purposes of the Principle of Priority but not for those of the Principle of Homonymy) (Insecta, Coleoptera). Opinion 2083

Cyphosoma Mannerheim 1837, Bulletin de la Société Impériale des Naturalistes de Moscou, 1837(8): 91 (gender: neuter) (type species, by subsequent designation by Bílý, 2001, Folia heyrovskyana, 9(2): 150, of the replaced nominal genus Cyphonota Dejean, 1833: Buprestis tatarica Pallas 1773) (Insecta, Coleoptera). Opinion 2083

Cypraeigenus [Renier] [1807], [Tav. serv. Class. Conn. Anim.]: Tav. VIII (included in a work rejected for nomenclatural purposes). Opinion 427

cyprinacea Linnaeus 1758 [originally in Lernaea], Systema Naturae, Ed. 10, vol. 1, p. 655 (specific name of the type species of Lernaea Linnaeus 1758) (Crustacea, Copepoda). Opinion 481  

cyprinoides Linnaeus 1758 [originally in Mormyrus], Systema Naturae, Ed. 10, vol. 1, p. 327 (specific name of the type species of Mormyrus Linnaeus 1758) (Osteichthyes). Direction 57

Cyprinus Linnaeus 1758, Systema Naturae, Ed. 10, vol. 1, p. 320 (gender: masculine) (type species, by designation by Jordan & Gilbert, 1882 (Bull. U.S. nat. Mus., 16: 254): Cyprinus carpio Linnaeus 1758, Systema Naturae, Ed. 10, vol. 1, p. 320) (Osteichthyes). Opinion 77, Direction 56

CYPSELINAE Bonaparte 1838, Geogr. comp. List Birds Eur. N. Amer.: 8 (type genus: Cypselus Illiger, 1811) (suppressed under the plenary power for the purposes of the Principle of Priority but not for those of the Principle of Homonymy). Opinion 502

Cypselurus Swainson 1838 (gender: masculine), type species Cypselurus appendiculatus Swainson 1838(??), corrected original spelling (Opinion 26)

Cypselus Illiger 1811, Prodr. Syst. Mamm. Avium: 229 (a junior objective synonym of Apus Scopoli 1777). Opinion 502

Cypsilurus Swainson 1838 (gender: masculine), incorrect original spelling of Cypselurus Swainson 1838, type species Cypselurus appendiculatus Swainson 1838(??) (Opinion 26)

Cyrbasiodon Broom 1931, Records of the Albany Museum, 4: 163 (gender: masculine), type species by monotypy Cyrbasiodon boycei Broom 1931, with the endorsement that it is not to be given priority over the name Procynosuchus Broom 1937 whenever the two are considered to be synonyms (Therapsida). Opinion 2264.

Cyrnus Stephens 1836, Ill. Brit. Entomol., Mand., 6: 174 (gender: masculine) (type species, by designation under the plenary power: Cyrnus unipunctatus Stephens, 1836, Ill. Brit. Entomol., Mand., 6: 175, valid name: Philopotamus trimaculatus Curtis 1834) (Insecta, Trichoptera). Opinion 691

Cyrtodaria Reuss 1801, Repertorium Commentationum, vol. 1, p. 351 (gender: feminine) (type species, by subsequent monotypy by Gray, 1847, Proceedings of the Zoological Society of London, 15: 190: Mya siliqua Spengler 1793) (Bivalvia). Opinion 1414

Cyrtograpsus Carruthers 1867, Intell. Observ., 11: 369 (a junior homonym of Cyrtograpsus Dana 1851). Direction 37

Cyrtograpsus Dana 1851, Proc. Acad. nat. Sci. Philadelphia, 5: 250 (gender: masculine) (type species, by monotypy: Cyrtograpsus angulatus Dana 1851, Proc. Acad. nat. Sci. Philadelphia, 5: 250) (Crustacea, Decapoda). Opinion 85, Direction 37 

CYRTOGRAPTIDAE Bouček 1933, Prace geol.-palaeont. ustavu Karlovy University: T.P., 11 [footnote] (type genus: Cyrtograptus Lapworth 1873) (Graptolithina). Opinion 650  

Cyrtograptus Lapworth 1873, Geol. Mag., 10: table i (gender: masculine) (type species, by monotypy, through Cyrtograpsus Carruthers 1867: Cyrtograpsus murchisonii Carruthers 1867, in Murchison, Siluria (ed. 4), App.: 540) (Graptolithina). Opinion 650

Cyrtometopus Angelin 1854, Palaeontologica Scandinavica, p. 32 (gender: masculine) (type species, by monotypy: Calymene clavifrons Dalman 1827) (Trilobita). Opinion 1434  

Cystia [Renier] [1807], [Tav. serv. Class. Conn. Anim.]: Tav. VII (included in a work rejected for nomenclatural purposes). Opinion 436  

Cystidea Barrande 1868, Neues Jb. Miner. Geol. Paläontol., 1868: 694 (suppressed under the plenary power for the purposes of the Principle of Priority but not for those of the Principle of Homonymy). Opinion 927  

Cystigenus [Renier] [1807], [Tav. serv. Class. Conn. Anim.]: Tav. VII (included in a work rejected for nomenclatural purposes). Opinion 427 

Cystioceras Börner 1912, in Schille, Spraw. Komisji Fysiogr. Kraju, 46: 126, 127 (suppressed under the plenary power for the purposes of the Principle of Priority but not for those of the Principle of Homonymy). Opinion 1193 

Cystophora Nilsson 1820, Skand. Fauna, Dagg. Djur.: 382 (gender: feminine) (type species, by designation by Allen 1880 (U.S. geol. geogr. Surv. Terr., Misc. Publ., 12: 273): Phoca cristata Erxleben 1777, Syst. Regni Anim.: 590) (Mammalia). Opinion 91, Direction 24

Cystophora Yabe & Hayasaka 1916, J. geol. Soc. Tokyo, 23 (No. 271): 70 (a junior homonym of Cystophora Nilsson 1820). Direction 24

Cytamoeba Danilewsky 1891, Ann. Inst. Pasteur, 5(12): 762 (included in a work rejected for nomenclatural purposes). Opinion 283  

Cytherigenus [Renier] [1807], [Tav. serv. Class. Conn. Anim.]: Tav. VII (included in a work rejected for nomenclatural purposes). Opinion 427

Cytosporon Danilewsky 1891, Ann. Inst. Pasteur, 5(12): 762 (included in a work rejected for nomenclatural purposes). Opinion 283  

Cytozoon Danilewsky, 1891, Ann. Inst. Pasteur, 5(12): 780 (included in a work rejected for nomenclatural purposes). Opinion 283  

CYZICIDAE Stebbing 1910, Ann. S. Afr. Mus., 6(4): 486 (type genus: Cyzicus Audouin 1837) (Crustacea, Branchiopoda). Opinion 553

Cyzicus Audouin 1837, Ann. Soc. entomol. France, 6: x (gender: masculine) (type species, by monotypy: Limnadia tetracera Krynicki 1830, Bull. Soc. imp. Nat. Moscou, 2(11): 176) (Crustacea, Branchiopoda). Opinion 553