134 THE NAUTILUS. 



above Ruidoso, N. M., sent by Prof. Cockerell, one with the spire 

 broken, measure : 



Alt. 8.8, — 8 mm. 



Diam. 14.1, 14.8, 13 mm. 



Whorls 5£, — b\. 



Ribs on the last whorl 60, 48, 46. 



The number of ribs on the last whorl is only approximately stated, 

 since on account of irregularities and minor wrinkles or ripples it is 

 impossible to make a quite definite count. 



The weak trace of a parietal tooth is visible in one of the specimens. 



The two specimens examined by Mr. Bartsch measure 8.2 x 15 mm. 

 The number of ribs is not stated. 



These specimens are intermediate in character between the smaller 

 and more strongly-wrinkled examples of A. rhyssa, collected by Mr. 

 Ashmun, and the following form. 



Thirteen examples, all dead and bleached, were taken by Mr. F. J. 

 Phillips on the north slope of a small brook near Nogal Creek, at an 

 elevation of 7500 ft., Lincoln Co., N. M., and recently sent to one 

 of us, one being drawn in figs. 1, 2 of plate VIII. In general char- 

 acter the lot is quite uniform. There are 30 to 35 ribs on the last 

 whorl ; in a few cases as many as 40, by splitting or breaking up of a 

 number of ribs. Ten of them, unbroken, measure as follows : 



Alt. 8.1, 8, 7.9, 7.5, 8, 7.8, 7.8, 7.5, 7.1, 6.6 mm. 



Diam. 13, 12.9, 12.8, 12.25, 12.2, 12, 12, 12, 12, 11.5 mm. 



In 8 out of 10 fully adult shells a parietal tooth is developed, varying 

 from a mere trace in some to a well-developed though small tooth in 

 three or four. In two fully adult shells there is no trace of a tooth. 

 A low basal tooth is present in all, but in two or three it is barely 

 perceptible. The largest shell has 5^ whorls, the smallest barely 5. 



This colony has the character of townsendi — small size and heavily- 

 ribbed surface — more emphatically expressed than in the original 

 townsendi, and compared directly with rhyssa it appears to be quite 

 distinct; yet it is connected with rhyssa through the more finely- 

 ribbed forms from above Ruidoso, so that the use of a trinomial 

 seems to express its relations better than an arbitrary specific 

 separation. 



Ashmunella rhyssa (Ckll.) Plate VIII, figs. 3, 4, 5. 



Professor Cockerell having found the unique type specimen of 



