1904.] NATURAL SCIENCES OF PHILADELPHIA. 419 



Thus the smallest adult is quite equal to the average recent shells. 

 A few selected specimens of the fossil and recent shells can hardly be 

 distinguished. Many of the fossils do not have the callosity. 



Locality 816 has great quantities of these shells so firmly cemented 

 together that most of them are worthless as specimens. They have 

 the peculiar spheroidal upper surface, but the perforation is wider 

 than in the series from locality 808 — not so wide, however, as in the 

 recent. Several specimens here occur below some fragments of Poecilo- 

 zonites nelsoni in stalagmite, apparently showing that they were there 

 previous to the extinction of nelsoni. 



Broken and immature specimens from locality 808 show that the 

 umbilicus was not much narrower than that of the recent variety imtil 

 the last whorl had commenced to grow. The peculiar contour is also 

 less noticeable prior to the last whorl. Thus in their smaller number of 

 whorls, their less rounded contour, and their larger umbihcus, the 

 present snails seem like an imdeveloped or degenerate race of the 

 former species. 



It is possible that this fossil variety is what Pfeiffer {Monographia, 

 I, p. 80) mistook for Helix ochrolcuca Fer. 



Pcecilozouites reinianus Pfr. 



Helix reiniana Pfeiffer, Malak. BL, XI, 1863, p. 1. 



P. reinianus Pilsbry, Proc. Acad. Nat. Sci. Phila., 188S, p. 290; 1889, p. 85. 



I found this species in every deposit examined except No. 807. 

 Further search would doubtless show it there also. At locality 815 

 many fine specimens were embedded in stalagmite. They show the 

 typical color-pattern, with the dark marks changed as usual to reddish, 

 and the lighter ground to ivory-yellow. 



The largest specimen from No. 815 measured.... Alt. 7 Diam. 13 mm. 



The largest from No. 808 _ __.... 12 



The largest from No. 806 -. 11.5 



The largest from the pocket at No. 814 - — . 11 



The largest recent, lent by Mr. Bryant 6 11.3 



My largest recent 5 10.3 



From Town Hill (locality 819) come some good specimens of var. 

 qoodei Pils, Examples of these measure: 



Alt. 4 Diam. 10 Umb. 4 mm. 



3.5 9.3 3.4 



3.7 10 4 



The species is not so uniformly common as Pcccilozoniies circiim- 

 prmatus, but is very abundant in some places, for example, near 

 locality 806. It would be interesting to learn whether its place in the 

 economy of nature is different from that of the following species. 



