THE NAUTILUS. 89 



pended, and when a passing fish touches them they fasten upon it by 

 means of the hooks, and the glochidium is wrenched from its moor- 

 ing. I observed frequently the sudden jump which my goldfish 

 made, and I afterwards found glochidia attached to ihem. 



A NEW ZONITOID SHELL FROM THE MIOCENE, FLORISSANT COLORADO. 



BT T. D. A. COCKERELL. 



Although fresh-water shells (^Lyrnnea, Planorbis and Sphcerium) 

 are abundant in the Florissant shales, terrestrial species are ex- 

 tremely rare. In 1906 we found a species of Omphalina, in a frag- 

 mentary condition. The 1907 expedition has yielded a better- 

 preserved specimen which is referred to Vitrea. 



VlTREA FAGALIS n. Sp. 



Diameter 7 mm. ; with seven and a half closely coiled whorls, the 

 first three not increasing at ail, but having a uniform diameter of 

 about 340 micromillimeters ; the fourth barely larger, diam. about 

 357 m. ; the fifth with diam. about 391 m. ; the sixth twice as 

 broad as the inner ones; the seventh much larger, diam. 1| mm. 

 Last whorl very smooth and shining, not or hardly striate, but inner 

 whorls delicately striate, with the exception of the apical whorl and 

 a half, which are quite smooth. Spire gently convex, the sides 

 regularly ascending to the apex. 2so internal lamella?, so far as can 

 be seen. One example, with reverse ; on a slab with a leaf of Fag%is, 

 showing that it probably lived in the proximity of that tree. 



This shell appears to be a Paravitrea, very close in all respects to 



Vitrea andrewsa. In the number of whorls and absence of in- 

 ternal lamella;, it is like V. plaeentula ; but the whorls appear to be 

 more closely coiled than in that species, and the radial sculpture is 

 much closer and less regular. 



The resemblance of the Florissant flora to that of the uplands of 

 the southeastern states has already been noted ; the discovery of 



Vitrea fagalis, and the previous finding of Omphalina, point in a 

 similar direction. 



