OP CONCIIOLOQY. 245 



fine spiral lines; spire depressed, suture deeply impressed; 

 umbilicus wide and deep, lip margins connected by a callus 

 on the body. 



Diam. 37, height 13 mill. 



San Diego, Cal. 



Differs from all others of the group in its large size, and 

 color. The decussated surface, large umbilicus and rounded 

 lip distinguish it from II. Vancouver ensis, Lea. 



2. Macrocyclis Vancouverensis, Lea. 



Plate 3, figure 6. 



Large, whorls 5, the superior part of the last one flattened 

 upon approaching the aperture, rounded beneath; bright yel- 

 lowish-green, shining, roughly striate, with very slight revolv- 

 ing lines, suture moderate, umbilicus of moderate width and 

 deep. 



Diam. 30 mill. 



Oregon and Washington Territory. 



3. Macrocyclis sportella, Gould. 



Plate 3, figure 7. 



Medium size, whorls 5, the superior part of the last one flat- 

 tened upon approaching the aperture, rounded below; very 

 light apple-green, dull, very closely and sharply striate, reticu- 

 lated by slight, revolving lines; suture moderate, umbilicus 

 moderate and deep. 



Diam. 18 mill. 



Oregon, California. 



With same number of whorls, is much smaller than No. 2, 

 and more sharply striate. Messrs. Binney and Bland consider 

 the two identical, but the differences are permanent in many 

 specimens before me. 



4. Macrocyclis concava, Say. 



Plate 3, figure 8. 



Medium, whorls 5, superior part of last one flattened towards 

 the mouth, well rounded beneath ; light-horn color or greenish, 

 but almost white; slightly striate, suture well impressed, um- 

 bilicus rather wide and deep. 



