Helix turhiniforinis^ Pfeiffer. 81 



In tlie Genus Bulimulus^ however, the form of jaw under 

 consideration is not constant, as that of B. dealbatus, kSay, has 

 distinct anterior ribs. 



Helix turhiniforinis is placed, by Albers and v. Martens, in 

 the subgenus Microphysa. 



The lingual membrane is long and quite narrow, composed 

 of numerous oblique rows of about 25-1-25 teeth. Centrals 

 large in proportion to the laterals, siibquadrate, with broadly 

 reflected triscuspid apex, the cusps very globose, the two outer 

 ones unusually small and distant from the middle cusp ; 

 laterals like centrals, but bicuspid ; marginal teeth wide, low, 

 with small, stout, irregular denticles. 



The jaw and lingual membrane above described M'ere re- 

 ceived, already mounted, through Governor Kawson, from Mr. 

 Henry Vendryes of Jamaica, by whom they were taken from 

 a Jamaica specimen, and who noticed and has corresponded 

 with us on the peculiarity of the jaw. 



BiiHmnliis laticinctii§^ Gr"PPy- 



(Plate II., Figs. 1, 5.) , 



A mounted lingual membrane of this Dominica species was 

 received from W. H. J. Lechmere Guppy, of Trinidad. 



Lingual membrane long, and quite broad in comparison to 

 its length, composed of numerous waving rows of teeth. Cen- 

 trals subpyrauiidal, the base excavated, the apex not pointed, 

 but bluntly rounded and recurved into a stout obtuse long cusp, 

 which is unequally divided into two blunt, stout lobes. Later- 

 als very much longer and larger than the centrals, long, narrow, 

 obliquely recurved into a greatly developed, unequally tri- 

 lobed cusp. Marginals but little modified from the laterals in 

 shape, but narrow, denticulated on the outer side of their re- 

 flected cusp, which last is bicuspid rather than trilobed. 



Fig. 1 represents the central and lateral teeth ; Fig. 5 one of 

 the marsrinals. 



