82 On the Lingual Dentition. 



Buliiiinlu^ Bahaiiiensis, Ffr. 



i (Plate II., Figs. 3,4.) 



A specimen from ISTew Providence, received from Governor 

 Ravs^son, furnished the lingual membrane and jaws here de- 

 scribed. 



Jaw long, low, slightly arcuate, composed of over fifty sepa- 

 rate plates, in some places divided by distinct, though narrow 

 ribs. In two of the three jaws examined, the central plates are 

 chevroned on the median line, leaving a distinctly triangular 

 plate at the upper centre, whose base is up, its apex pointing 

 downward. In the third specimen the plates are obliquely ar- 

 ranged, from above and outward to within and below, as on 

 the whole surface of the jaw, but they reach quite across it, 

 leaving no central triangular plate. The jaw is interesting, as 

 it combines the characteristics of separate plates and distinct 

 ribs. 



Lingual membrane (PI. II., Figs. 3 and 4) as already de- 

 scribed in B. laticinctus. The points of the cusps, however, 

 are more acute than in that species. 



EXPLANATION OF PLATE II. 

 Fig. 1. Svlimulus laticinctus, to show the cusps of the central and 

 lateral teeth. 

 " 2. Helix turhiniformis. Jaw, 

 " 3. JBulimulus JBahamensis. To show the cusps of the marginal 



teeth. 

 " 4. Same as Fig. 3. The cusps of central and lateral teeth. 

 " 5. Same as Fig. 1. One marginal tooth. 



