TRACHELIPODA. 85 



the animal advances in age, and provided with a sinus at 

 the lovi'er part. 



Genus 23— STROMBUS LinncBus. 



Generic Character. — Shell ventricose, base terminating 

 in a short truncated, emarginated canal; right lip dilating 

 with age into a simple, entire wing, lobed or crenulated 

 above, and provided with a sinus beneath, separated at the 

 base from the canal or notch ; aperture provided with a 

 long narrow horny operculum. 



Strombiis Auris-Diance Diana's Ear Strombus. Plate 



XI. fig. 23. Oblong-ovate ; spire acute, tuberculated, and 

 transversely striated ; base recurved ; outer lip thick ; an- 

 terior lobe with a finger-like termination. Three inches 

 and a quarter long. Inhabits the Indian ocean. 



Ge7ius 24 — PTEROCERA. —Za??iarcA. 



Generic Character Shell oblong-ovate, ventricose, ter- 

 minating in a lengthened canal ; outer lip dilating with age 

 into an expanded, rayed, or digitated wing, with a sinus 

 near the base ; spire short. 



Pterocera Chiragra. — The Knotty Pterocera. Plate 

 XI. fig. 24. Ovate, tuberculated, with six digitated, canali- 

 culated rays, which are closed over in the adult shell ; outer 

 lip internally striated. Six inches and a half long, exclusive 

 of the digitated lobes. Inhabits the Indian ocean. 



Genus 25 ROSTELLARIA— iamarc/^. 



Generic Character — Shell fusiform or sub-turreted, ter- 

 minated below by a beaked canal ; outer lip entire in some 

 species, and dentated in others, more or less dilated by age ; 

 with a sinus near the canal. 



Rostellaria Pes-pelecani. — The Pelican's Foot Ros- 

 TELLARiA. Plate XI. fig. 25. Turreted, flesh-coloured or 

 white ; body and volutions longitudinally ribbed, and crowned 

 with papillae ; base of body papillose ; outer lip palmate, 



