MURICID^. Ill 



tricose ; apertiire wide ; columella arcuated ; inner lip excavated, 

 corrugated at the fore-part. P. planospira. Lam. (xliv, 18). 



THALESSA, H. and A. Adams. Spire elevated, whorls spinose, 

 angulated at the upper part ; aperture moderate ; columella 

 rounded, tubercular in front ; outer lip nodulous internally. P. 

 hijypocastaneum, Lam. (xliv, 19). 



STRAMONiTA, Schum. Spire elevated, whorls simple or nodu- 

 lous; apertux-e moderate, produced anteriorly; columella rounded, 

 simple in front. P. Floridana, Conr. (xliv, 20). 



TROCHiA, Swains. Whorls separated by a deep groove ; inner 

 lip thickened, convex, striated ; aperture with a very short canal. 

 P. cingulata, Lam. (xliv, 21). 



POLYTROPA, Swains. Spire acuminate, whorls foliated or tuber- 

 culose ; inner lip flattened ; canal small, oblique ; aperture 

 narrowed at the fore-part. P. lapillus, Linn, (xliv, '22). 



CRONiA, H. and A. Adams. Shell ovate ; spire acuminated ; 

 apei'ture moderate ; inner lip callous at the upper part ; columella 

 straight, simple anteriorly. P. amygdala^ Kiener (xliv, 23), 



PURPURELLA, Bcllardi, 1882. Aperture with a posterior canal, 

 defined \>j callous margins. P. canaliculata, Bellardi. Tertiary ; 

 Northern Italy. 



TAURASIA, Bellardi, 1882. Aperture canaliculate posteriorly, 

 with callous margins; columella with an anterior plication. 

 P. subfusiformis, d'Orb., and two other species. Tertiary ; 

 Northern Italj^ Neither this nor the preceding group possesses 

 characters of much importance. 



[SiNUSiGERA, d'Orb. 



S^ii/n.— Cheletropis, Forbes. 



Examples. — S. cancellata, d'Orb. (xx, 47). S. Huxleyi, Forbes 

 (Ixxxvii, 13). 



Turbinate, imperforate, dextral or sinistral, with a smooth, 

 striate or tuberculate surface and frequently, a keeled periphery ; 

 aperture channeled in front, peristome thickened, reflected, with 

 one or two claw-like lobes. 



The animal has four arms, arranged in cruciform manner and 

 used for swimming. There are two tentacles, and the eyes, well- 

 formed, are situated on the outer side of their bases. Respira- 

 tory siphon short, being a simple fold of the mantle. Foot large 

 and ver}^ mobile, furnished with a small, thin spiral operculum ; 

 unprovided with a float. The dentition (xx, 48) has been sup- 

 posed similar to that of the Muricidse — and the species have, 

 consequently' , been referred, as larval forms to that group. 



Dr. Jousseaume has established the identit}^ of a species of 

 Sinusigera with Purpura haemastoma, of which it is the larval 

 form — his series of specimens of various ages, collected at Ben- 

 guela, on the West Coast of Africa, showing a gradual develop- 



