156 INVERTEBRATA OF MASSACHUSETTS. 



Figure 5. 

 State Coll., No. 265. Soc. Cab., No. 2415. 



Dentalium denlalis, Lin. ; Sijst. JVV/<., 12G3. Born ; Mus., t. 18, f. 13. Maton 

 and Rackett; Lin. Trans., viii. 237. Deshayes ; Mem. de la Soc. d'Hist. 

 J^at., ii. 3.53, pi. 16, f. 9, 10. Lam. ; An. sans Vert., v. 595. 



Dentalium striatum, Montagu ; Test. Brit., 495. 



Dentalium attenuatum, Say ; Journ. Acad. JVat. Sc, iv. 154, pi. 8, f. 3. 



Shell slender and tapering, curved like an elephant's tusk, the 

 tip cut off, leaving a very small opening. Surface rather glossy, 

 yellowish-white, marked with about twenty closely arranged, un- 

 equal, rib-like stris, running the whole length of the shell. 

 Length about an inch ; diameter at the larger end about | inch. 



I am enabled to add this shell to our list through the kindness of my 

 friend W. W. Wheildon, of Charlestown, who sent me the specimens, 

 accompanied by the following memoranda. 



" Two specimens of De^italiuni were taken from the stomachs of cod- 

 fish, in the Spring of 1839. They were both found to have penetrated 

 the entrail of the fish, and were firmly fixed there. They had proba- 

 bly been in the fish for some length of time. Both specimens were 

 unfortunately eroded, one of them so much so that it is quite impossible 

 to determine any of its characters, except its size, its markings being 

 entirely obliterated. In the other specimen the striae are distinct, and 

 seem to conform to the D. dentalis of the coast of England. Twenty 

 to twenty-two striae may be counted on its surface." 



Family CALYPTrAcEA, Lam. 



Shell basin-shaped, serving as a cover to the animal ; distinguished from 

 the preceding family by the branchi<£ being situated in a peculiar cavity upon 

 the back. 



Genus CEMORIA, Leach. 



Shell small., like Patella, ivilk the apex elevated and curved 

 forivards, and with a fissure just behind the apex. 



Cemoria NoachIna. 



Shell small.) while., conical., covered with unequal., radiating 

 ribs ; apex curved Jorivards, and perforated obliquely backicards. 



Figure 18. 



