1904.] NATURAL SCIENCES OF PHILADELPHIA. 421 
Zonitoides minusculus Binn. 
Locality 807, and recent. Its abundance in the one deposit and 
absence in the others is a little surprising. 
_Zonitoides bristoli n. sp. Pl. XXXVI, fig. 13. 
Shell resembling Zonitoides minusculus in general form, but much 
smaller, only moderately umbilicate, white, costulate, and densely 
sculptured with spiral lines ; composed of 3 convex whorls. Apex 
somewhat elevated. Aperture lunate, the outer and basal margin 
more uniformly curved than in Zonitoides minusculus, and the preced- 
ing whorl cutting out a greater arc. Peristome simple, thin. Costule 
regularly spaced, coinciding with growth lines. The spaces between 
them crowded with fine strie. A close, regular, spiral sculpturing 
crosses these lines and gives the costule a slightly tubercular appear- 
ance. 
Alt: .7 Diam. 1.17 mm. 
Named in honor of Dr. C. L. Bristol, of New York University, Associate 
Director of the Bermuda Biological Station for Research. 
One specimen from each of localities 807 and 818; the type from the 
latter place. 
Succinea bermudensis Pir. 
x, S. bermudensis Pfr., P. Z. , 1857, p. 110; Monographia, IV, p. 817. 
S. barbadensis Pilsbry, nae Conn. Acad. 3) 2% Pp: 502: 
Localities 807, 806, 818, 808, 809 and recent. In the absence of alco- 
holic specimens of S. barbadensis I have given up that name and re- 
turned provisionally to the name bermudensis. Its presence as a fossil 
makes it not unlikely that it may be proved distinct from S. barbadensts. 
This is another species that was formerly larger than now. The largest 
fossil, from locality 808, measures alt. 13, diam. 7mm. The largest 
out of 30 recent specimens lent by Mr. Bryant has alt. 12, diam. 6.3 mm. 
Helicina convexa Pfr. ; 
If this species were indigenous we could expect it to be as abundant 
formerly as itis now. Instead of that it seems to be entirely absent 
from the beds I examined. The evidence seems to me strong thatits 
real home is elsewhere. 
