38 PUPISOMA. 



comes higher relative to the diameter with age. C. B. Adams' 

 measurement of the altitude was probably of the axis, not to 

 the base of the lip. 



This minute snail certainly inhabits a vast area, entirely 

 similar specimens occurring from about 30 north latitude 

 to about 24 south. 



It may be inferred that C. B. Adams found this species on 

 leaves of the yam (Dioscorea). S. N. Rhoads reported it as 

 1 ' numerous in certain localities [about Miami, Fla.] on the 

 under surface of the leaves of magnolia and of palmetto ; on 

 the latter sometimes a score can be taken from a single leaf. ' ' 

 Morelet found Helix punctum, which seems to equal dios- 

 coricola, on leaves of trees. 



The species is probably found all over Jamaica, as the 

 localities given above are on the south and north shores and 

 the high interior. Several unlocalized Jamaican lots from 

 the older collectors are also in our collection. In one of the 

 shells from Montego Bay there are strong wrinkles at rather 

 wide, unequal intervals; otherwise the Jamaican specimens 

 are much alike. Most specimens from Florida agree with 

 those of Jamaica; in some the spiral lines are somewhat 

 weaker. 



Specimens from the Canal Zone and from Vieque are 

 rather small, the striae and spiral lines fine and delicate 

 though distinct. Probably they are not absolutely mature. 



The following appear to be synonyms. 



Helix ccEca Guppy, described from Trinidad, is, according 

 to a series received from that author many years ago, prac- 

 tically typical dioscoricola. The spiral lines are weak, barely 

 discernible on the upper part of the last whorl in some speci- 

 mens, but in others distinctly developed throughout, though 

 not strong. One of this lot is figured, pi. 4, fig. 5. Pfeiffer's 

 figure, doubtless from a specimen from Guppy, was copied 

 by Tryon in MANUAL, vol. II, pi. 53, figs. 46, 47. Guppy de- 

 scribed it as costulate, Pfeiffer as stria tulate ; the latter term 

 is more appropriate. Two examples measure: Length 1.6, 

 diam. 1.6 and 1.65 mm. 



Helix punctum Morelet is in no way differentiated from 



