TRACHELIPODA. 77 



a canal at the base ; columella with from three to five oblique, 

 transverse, and compressed plaits. 



Somewhat allied to both Murex and Voluta, but differing from the former 

 in the want of varices, and from the latter, from having no canal ; and al- 

 though also, somewhat like the Fasciolaria, they can be distinguished from 

 tliit ^enus by the position of the plates on tlie columella. 



Turhinella pyrum. — The Pear. Shaped Turbinella. Plate 

 XII. fig. 8. Pear-shaped ; yellowish-white, with irregular red- 

 dish-brown spots ; spire short, mucronate ; apex mammilliform ; 

 beak long ; columella with four plaits ; in adult specimens, the 

 shell is covered with a very thick opaque yellow-brown epider- 

 mis. Six inches long. Inhabits the Indian ocean. 



Gems 35.— PLEUROTOMA Lamarck. 



Generic Character. — Shell turrited or fusiform, terminated 

 below by a straight canal, of greater or less length j outer lip 

 with a notch or fissure at the upper part ; aperture with a small 

 horny operculum. 



Pleurotoma nodifera. — The Javanese Pleurotoma. Plate 

 XII. fig. 7. Fusiform, turrited ; volutions somewhat angulated, 

 upper ones smooth ; under volutions and body transversely stri- 

 ated with angulated oblique nodules at the suture ; outer lip 

 deeply crenulated, with a large notch ; reddish-yellow. One inch 

 and a half long. Inhabits the seas around Java. 



Genus 36 CBRITHWJM.—Bruyuiere. 



Generic Character, — Shell turrited ; aperture oblong, oblique, 

 terminated at the base by a short, truncated, recurved canal, 

 without a notch ; the outer lip with a groove at its upper ex- 

 tremity ; aperture provided with a small horny operculum. 



This genus is allied to the Pleurotoma, but the aperture is devoid of the 

 slit on the right margin. 



Cerithium semigranosum — The Semigranulated Ceri- 



thiUxM. Plate XII, fig. 9. Fusiform, turrited; apex acute; 



transverse minute striae, and sulcated granulations ; the suture 



with double spiral rows of large granules ; colour reddish-brown. 



One inch and a half long. Inhabits the seas of New Holland. 



G 3 



