University of Michigan 



PLATE I 



Figs. I, 2, 3. Plaiiorhis anfrosus jordanensis. Type, x 3. 



Fig. 4. I'laiiorbis uuii-osus jordanensis. Cntype, I^Ius. Zool., 



Univ. of Mich., No. 27442. ^lost inflated specimen, x 3. 



Fig. 5. Planorbis antrosns jordanensis. Cotypc, Mus. Zool., 



Univ. of Alicli., No. 27441. Example of abruptly descend- 

 ing aperture, x 3. 



Figs. 6, 7, 8. ferrissia niichiijinuvisis. Type, x 10. 



