CECUM. i 7 



apparatus consists of two plumes or one only. Young 

 shells are more convex and tapering, and their mouth 

 is bell- shaped. The fry is exceedingly curious. It is 

 long and twisted, not unlike the horn of an antelope ; 

 its posterior termination is formed of a minute coil of 

 two whorls. The concentric ridges are then percep- 

 tible towards the mouth only, and are very slight ; the 

 rest of the shell is quite smooth and glossy. I am in- 

 debted to the Marquis James Doria for baby specimens 

 which he dredged at Spezzia. 



This is the Dentalium imperforatum of Adams ' On 

 the Microscope ' (from Walker's figure) , as well as of 

 Montagu who described the young as D. trachea ; but 

 the latter specific name is now generally used. Brown 

 called it Brochus striatus and B. trachiformis ; Cailliaud 

 spelt the name C. trachcea. The fry is Costa's Spiroli- 

 dium Mediterraneum. 



Brochus annulatus and (young) B. reticulatus of Brown 

 ("Loch Strangford ' ) is an exotic species. Dr. P. 

 Carpenter found no less than 53 specimens of it by 

 washing the common sponge of commerce from the 

 West Indies ; and Mr. Bean has some from Aden. I 

 mention this because C. annulatum has been noticed and 

 figured in the ' British Mollusca ; on the authority of a 

 specimen received by Mr. Alder from Mr. Clark. Flem- 

 ing's description of his Orthocera trachea (Br. An. p. 237) 

 evidently applies to the same foreign species. 



B. Thin and smooth ; operculum, convex. Brocliina, Gray. 



2. C. glabrum *, Montagu. 



Dentalium glabrum, Mont. Test. Br. p. 497. C. glabrum, F. & II. iii. 

 p. 181, pi. lxix. f. 5. 



Body pure-white, with the lines forming the canal or groove 



* Smooth. 



