208 CYPR^A. 



Dimensions. — Length 63 mm.; breadth 39 mm. 



Form, and Loc. — Eocene: Muddy Creek, Victoria. 



G. 5478. An example of the adult. Purchased. 



Subgenus EROSARIA, Troschel. 



[Gebiss der Schnecken, Bd. i. 1863, p. 210.] 



Aricia, Sowerby and Gray, Conch. Illust. and Desc. Cat. Shells, 

 1832, p. 7 {non Savigny, 1817). 



Shell smooth on the dorsal surface ; flattened underneath ; 

 columella not excavated in front; aperture crenulate, dentate or 

 ridged on both the inner and outer margins. 



Type. — Cupran erosa, Linnaeus. 



Cypraea (Erosaria) gigas, M'Coy. 



1867. Cyprma gigas, M'Coy, Ann. Mag. Nat. Hist. 3rd ser. vol. xx. p. 438. 



1875. Cijpraa {Aricia) gigas, M'Coy, Prod. Pal. Vict. dec. ii. p. 19, pi. xv. ; 



pi. xvi. fig. 2 ; pis. xvii. and xviii. fig. 1. 



1876. C'gpraa (Aricia) gigas, M'Coy, id. dec. iii. p. 35, pis. xxviii. and xxix. 



fig. 1. 

 1890. Cypraa gigas, Tate, Trans. Eoy. Soc. South Aust. vol. xiii. pt. 2, 



p. 212. 

 1893. Cyprma gigas, Tate and Dennant, id. vol. xvii. pt. 1, p. 221. 



This is the largest known species of Cyprcea, living or fossil. 

 It is much inflated dorsally, base flattened ; inner margin smooth 

 within, flattened near the anterior canal, which is deep, narrow, 

 elongate, and projects upwards ; outer margin tumid, furnished 

 with nine or ten obsolete obtuse teeth near the anterior end, and 

 a few also near the posterior extremity ; posterior canal obliquely 

 truncate, bent upwards, and adherent to the spire. 



This is by no means a typical Erosaria, the inner margin not 

 being dentate or plicate; but Sir E. M'Coy states' that under 

 certain circumstances, "faint indications of teeth may be detected"; 

 in other respects, and in the broad sense, it conforms fairly well to 

 that subgenus. It is allied to Gisortia, Jousseaume, which, how- 

 ever, is t3pically largely tuberculate or keeled on the surface. 



Dimensions. — Length 8f inches; breadth 5| inches. 



Form, and Loc. — Eocene : Muddy Creek, Victoria. 



1 Prod. Pal. Vict. dec. ii. 1875, p. 19. 



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