6 Dentition of Pulmonate Mollushs. 
Leptoloma. 
Only one species examined :— 
Leptoloma fuscocinctu, Ad. Jamaica. 
Jaw thin, arcuate, high, ends bluntly truncated; with perpendicular striae; 
cutting edge with a median projection. 
Lingual membrane (Pl. V, fig. I) as in Plagioptycha. 
Achatinella. 
In Annals of Lyceum of Nat. Hist. of New York, X, 331; 
XI, 190, are given in detail my observations on the anatomy of 
Achatinella. here give a summary only of what relates to the 
jaw and liugual dentition. 
Most of the specimens examined were sent by Mr. Gulick. 
A few were received from the Museum of Comparative Zoology. 
I have here grouped the species according to von Martens’ 
arrangement and sub-genera. I will state that, of Mr. Gulick’s 
arrangement, the species examined represent the sub-genera— 
Achatinella, Bulimella, Apex, Partulina, Auriculella, Laminella, 
Amastra, Leptachatina,—all except Newcombia: Careliais treated 
below. 
The result of my examination may be briefly stated, viz.: 
that I find two types of dentition, one (w) including the species 
of Partulina and Achutinella, s. 8. ; the second (6) comprising 
all the species exumined, of Newcombia, Laminella, Leptachatina. 
Bulimella, Apex and Labiella, of von Martens’ arrangement, 
were not examined. Of. these we may expect to find the first 
two agreeing with my first section (a) in dentition; the last, with — 
my second (0). 
In the section (@) suggested by me, the species are all charac- 
terized by a Jaw so extremely delicate as to be found with great 
difficulty. It cannot be extracted by potash. It is arcuate, ex- 
tremely thin, transparent, with blunt ends. ‘The lingual mem- 
brane agrees with that figured by Heynemann of A. balimoides. 
It is very broad in comparison to its length. In one lingual 
there were 175-1-175 teeth. They are arranged en chevron. 
There is but one form of tooth for centrals and side teeth (it is 
difficult to call the latter laterals or marginals), but the centrals 
are somewhat smaller and symmetrical. The base of attachment 
