Dentition of Pulmonale Mollusks. 93 



Wisps and no side cutting points, and with a very broad, short median cusp, 

 bearing a short, widely-expanded, square vdge (as it cannot be called a 

 point). Laterals like the centrals, but asymmetrical, as usual, and with an 

 asymmetrical cutting edge larger than in the central tooth. The cutting 

 edge becomes more developed as the teeth pass off laterally, in proportion 

 to the base of attachment and the cusp also. Thus the marginals become 

 formed without any splitting of the inner cutting point, or any development 

 of a side cusp and cutting point, excepting that on some of the teeth a blunt 

 obsolete side cusp may be shown. 



The form of this species from Gonave Island, Haiti, (Prof. Linden,) is 

 said by Mr. Bland to have a white, instead of a reddish brown, peristome. 

 The lingual membrane is figured on PI. IV, tig. H. The cutting points on 

 all the teeth are more produced than in the Cuban sagemon and Arangiana; 

 after the eighth tooth there is a decided side cutting point on the laterals 

 and marginals. The jaw is the same as in sagemon. 



Caracolus Arangiana, Poey. Cuba. Mr. Arango. 



Jaw (PI. XV r , fig. M) greatly arched ; ends blunt, scarcely attenuated ; 

 cutting margin with a blunt, median projection. 



Lingual membrane (PI. IV, fig. 1) with 33 1-33 teeth, arranged as in 

 sagemon'. The lower margin of the base of attachment seems delicately 

 fringed. 



Caracolus marginella, Gmelin. Porto Rico. Mr. R. Swift. 



The jaw differs from that of the other species examined, in having stout 

 anterior ribs. 

 Lingual membrane (PL IV, fig. J). 



Leucocbroa. 



Tlie genus Leucochroa is adopted by von Martens, the type 

 being Helix candidissima, Drap., a species whose anatomy has 

 been described by Moquin-Tandon as being more nearly related 

 to Zonites than to Helix. The genus is classed by von Martens 

 among the Vitrinea, the section of Helicea containing the genera 

 furnished with ribless anterior surface and median projection to 

 the jaw, and aculeate, marginal teeth to the lingual membrane. 

 Among the species catalogued by von Martens is Leucochroa 

 Boissieri, Charp. We find, however, that both jaw and lingual 

 membrane in this species indicate that the genus belongs to the 

 Helicea. 



Leucochroa Boissieri, Charp. Palestine. Mr. John Van 

 Nostrand. 



Jaw very low, long, arcuate ; ends but little attenuated, bluntly rounded ; 

 cutting edge with a decided median projection; anterior surface free from 



