Miscellaneous. 249 



to possess the characteristics of Leptolimncea, Swainson. The earliest 

 known species of Limnophysa is L. nitidula, Meek, which is asso- 

 ciated with Acella Haldemani, jnst mentioned. Two other species 

 from the Green-Eiver group of Wyoming are referred to that type, 

 namely L. vetusta and L. similis, Meek. 



Planorbis proper is represented hy P. (equal is, White, in the 

 Green-Eiver strata of Wyoming. Bathyomphalus has two represen- 

 tatives, namely P. (B.) Jcanabensis, White, and P. (B.) planocon- 

 vexus, Meek and Hayden ; both in the Laramie group. The former 

 comes from Southern Utah, and the latter from Montana. Gyrau- 

 lus appears to have several representatives in both the Laramie and 

 Green-Eiver strata : but G. militaris, White, from strata probably 

 of the Laramie period, is the only one yet published. 



A considerable number of species of the Physinae are known in 

 the Laramie, Wahsatch, and Green-Eiver groups ; and the subfamily 

 was well established before the first-named period. It is an inter- 

 esting fact, in confirmation of the latter statement, that a typical 

 species of PJiysa, P. Garletoni, Meek, has been found at Coalville, 

 Utah, in estuary strata which rest upon marine Cretaceous strata, 

 and have more than 1000 feet of similar marine Cretaceous strata 

 resting upon them. This is the earliest Physa known in American 

 strata. Physa pleromatis, White, is a widely distributed species in 

 the Wahsatch group of Wyoming, Colorado, and Utah ; but true 

 Physa is not common in the Laramie group, although that genus 

 prevailed both before and after. In the last-named group Bulinus 

 is somewhat common — B. atavus, White, and B. subelongatus, Meek 

 and Hayden, being published examples. 



The Helicinae appear to have been almost as diversely differenti- 

 ated during the Laramie, Wahsatch, and Green-Eiver epochs as 

 they are at the present day, no less than five of the subordinate 

 types embraced in that subfamily having been more or less satis- 

 factorily recognized among the molluscan faunas of these epochs. 

 Aglaia is represented by Helix peripheric, White, in the Green- 

 Eiver group of Utah ; and Arianta by H. riparia, "White, in the 

 same group of Southern Wyoming. Helix Jcanabensis, White, 

 seems to possess the distinguishing characteristics of Strobila. It 

 occurs in the upper part of the Laramie group of Southern Utah. 

 Patula is represented by Helix sepulta, White, in the coal-bearing 

 strata of Evanston, A\ r yoming, which belong cither to the upper part 

 of the Laramie group or the base of the Wahsatch, probably the 

 former ; and apparently also by an undcscribed species in the Green- 

 Eiver group of Wyoming. Triodopsis is represented by Helix evan- 

 stonensis, White, which is associated with H. sepulta, just men- 

 tioned. 



The Pupinse have been recognized only in the Green-Eiver and 

 Bridger groups, four species only having yet been discovered. The 

 true character of the aperture has been ascertained only in one of 

 these ; and they are therefore assigned with some doubt to the types 

 mentioned. Their diverse forms, however, indicate that a wide 

 differentiation had taken place in the Pupinae at that early time. 

 Pupa arenula and P. atavuncula, White, discovered in the Green- 

 Eiver strata of Wyoming, are referred provisionally to Pupilla, and 



