16 THE NAUTILUS. 



Young shells form a quite thin lip-callus at resting stages, 

 but these seem to be absorbed subsequently, as no opaque 

 streaks are visible in the adult stage. 



Height 6.7, diam. 15 mm. 



Locality. — A mile or two above the box of Dry Creek Canyon, 

 Station 70, south slope of the Mogollon Mts. (4 miles south of 

 the Little Whitewater station) ; elevation from 6000 to 7500 

 feet. Also at various stations mentioned below, in the same 

 canyon. 



Explanation of Plates. 



Note. — Figures on plate I, and figs. 1-3 on plate II, are If 

 natural size; figures 4-8 on plate II are natural size. 



Plate I. Fig. 1. Ashmunella tetrodon. Type and paratypes. 

 Station 72. 



Fig. 2. Ashmunella tetrodon. Station 79. 



Figs. 3, 3a. Ashmunella tetrodon. Variety with small 

 parietal tooth. Station 60. 



Fig. 4. Ashmunella tetrodon mutator. Station 60. 



Fig. 5. Ashmunella tetrodon mutator. Type and paratypes. 

 Station 80. 



Fig. 6. Ashmunella tetrodon mutator. Station 67. 



Fig. 7. Ashmunella tetrodon inermis. Type and paratypes. 

 Station 69. 



Plate II. Fig. 1. Ashmunella danielsi. Type and paratypes. 

 Station 57. 



Fig. 2. Ashmunella danielsi dispar. Type and paratypes. 

 Station 55. 



Fig. 3. Ashmunella pilsbryana Ferriss. 



Fig. 4. Sonorella peninsularis Pils. Type. Lower CaUfornia. 



Fig. 5. Sonorella ultima Pils. Type. Sinaloa. 



Fig. 6. Epiphragmophora ellipsostoma Pils. Type. Lower 

 CaHfornia(?). 



Fig. 7. Sonorella lioderma Pils. Tj^pe. Lower California. 



Fig. 8. Sonorella lohrii (Gabb). Type. Lower California. 

 (To be continued) 



