CO. A. White—Fresh-water and Land Mollusca. 45 
The comprehensive genera that embrace the minor types 
which are here more especially discussed or referred to are 
Inmnea, Planorbis, Physa, Helix, Pupa, Succinea and Unio 
. HELICINA. 
1. Acelia Haldeman. 9. Aglaia Albers. 
2. Leptolimnea Swainson. ~ 10. Arianta Leach. 
3. Limnophysa Fitzinger. 11. Patula Haldeman. 
12. Strobila Mo: 
NORBLN.Z. ; : 
4. Planorbis (typical), Guettard. ene eee 
5. Bathyomphalus Agassiz. . 
; 14. Lucocheila Ath. & Mart 
6. Gyraulus Agassiz. 15. Pupilla Leach. 
PHYSIN#. 16. Holospira? Albers.* 
1. Physa (typical) Draparnaud. , . 
8. Bulinus Adanson. 17. Brachyspira Pfeiffer. 
* 
It should be mentioned that these subordinate types were 
originally recognized among, and their names applied wholly 
to, living forms. The discovery of fossil forms of those types 
is a gratifying confirmation of their genuineness (time bein 
the crucial test of permanency), and proof of the sagacity of 
their authors. 
Acella is represented by A. Haldemani Whitet from the Lar- 
amie strata of Bear River Valley, Wyoming. With the prob- 
able exception of an undescribed form in the Green River 
and Hayden, from the Laramie strata of Montana, is a closely 
allied form. Limnea (Leptolimnea ?) minuscula White, from’ the 
* Holospira is placed here under the Pupine only conventionally. 
: ix patt : 
, in the follow- 
-) oi 
ee ee an 
Sur. west or the 100th Merid., vol. iv; U. S. Geol. Sur. 40th Parallel. vol. iv; 
mpson’s Rep. Great Basin Utah; and Proc. U. 8. National Museum, vol. iii. 
The in press). 
