132 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



EXPLANATION OF PLATE L 



Page. 

 Schloenbachia knighteni, sp. nov. 119 



Fig. I. Adult specimen. 



Figs. 2-3. Young shells. 



Fig. 4. Enlarged suture of young shell. 

 Schloenbachia blanfordiana ? Stol. 124 



Figs. 5-6. Adult shells. 



Figs. 7-9- Young shells. 



Fig. 10. Very young shell; X2. 

 Prionotropis branneri, sp. nov. 125 



Figs. 11-12. Adult shells. 



Figs. 13, 14, 15, 16. Young shells. 

 Mortoniccras ctrniilatum, sp. nov. 125 



Figs. 17-18. Ventral and side views of adult shell with spines. 

 Schloenbachia siskiyouensis, sp. nov. 119 



Figs. 19-20. Side and front views of adult shells; natural size. 

 Schloenbachia chicoensis Trask. 116 



Figs. 21-22. Side and front views of young shells. 



