LOWER CALIFORNIAN MOLLUSCA. I43 



EXPLANATIOX OF PLATES V, VI. 



Figiires 1 to 17 are of uatnral size. 

 Fig. 1. BiiUmithis ver/etus var. regexspizn, showing the colnmellar thick- 

 ening or tooth. 

 Fig. 2. Young of B. vegetus, the tipper translucent, the lower showing u 



slight angle on bodj'-whorl. 

 Fig. .3. A toothed specimen like fig. 1, broken to show the normal form 



of pillar. Exactly the same is found in toothed B. monte.zuma. 

 Fig. 4. A typical B. inscendens, showing the pillar more twisted. 

 Fig. 5. B. sjjirifer from La Paz, showing the strong tooth inside where 



the lamina begins. 

 Fig. 6. A typical B. inscendtrnn with a rudimentary tooth, more develoj^ed 



than in fig. 4. 

 Fig. 7. B. inscendcnn var. alta Dall, strongly sculptured, from Sierra La- 



guna. 

 Fig. 8. B. inscendenfi hri/cmti, the mountain form, called monticola Dall. 



These two have the pillar normal and no laminations. 

 Fig. 9. B. siifflatus, of largest size, having the epidermis only in a few 



narrow stripes. 

 Fig. 10. B. aujfiains var. chhichensix. An old thick-lipped specimen. 



Form near Binney's type. 

 Fig. 11. A half-grown B. su_fflatufi, with wide iimbilicus, the epidermis 



entire. 

 Fig. 12. B.pilula, larger than tj'pe, from San Jose del Cabo. 

 Fig. 13. B. xaiitusi, typical form, El Taste Mountains. 

 Fig. 14. B. xaniusi levis Dall {r=B. fjabhi var.? ) 

 Figs. 15, 16. Forms of B. xantusi ? from El Taste Mountains. 

 Fig. 17. B. artemisia, largest, from Sierra Laguua. 



Figures 18 to 25 are double natural size. 

 Fig. 18. Columna ramentosa ahhreviata. 

 Fig. 19. Columna ramentosa, typical. 

 Fig. 20. Melaniella eiseniana. 

 Fig. 21. Melaniella tasien-sis. 

 Figs. 22, 23. Planorbis anitenslti. 

 Figs. 24, 25. Planorbis peninsularis. 



Figures 26 to 31 are magnified 14 times. 

 Fig. 26. Surface of Bulimulus montezuma (white var.) 

 Fig. 27. ." " vegetus vegcxspiza. 



Fig. 28. " " inscendens hry anil (monticola). 



Fig. 29. " " xantusi (typical), fresh specimen. 



Fig. 30. " " artemisia " " " 



Fig. 31. " Columna ramentosa ahhreviata. 



