238 AMERICAN JOURNAL 



Bimcymons. — Length 1-9 in., length of aperture -45 in., width 

 of aperture "4 in., width of body whorl -oS in. 



LocaUty. — Hidden under loose volcanic I'ocks in the high table 

 lands of the interior of Lower California, especially about Moleje. 

 This, and its congener, are essentially mountain species, being 

 only found in the highest regions. 



Ohurvations. — This shell resembles U. costata, Gould, as 

 figured by Adams in Gen. Recent Moll., pi. 76, fig. 7. It differs, 

 however, in being more regularly tapering, and in being pro- 

 portionally more slender. 



Cylindrella (Urocopti?) irregularis, Gabb. — Plate 16, 

 fig. 4. 



Description. — Shell about an inch long, slender, spire irregu- 

 larly tapering, the first three whorls being of the s;ime diameter, 

 the next five to seven whorls increasing steadily, after which the 

 remainder are nearly of the same diameter : apex not always 

 exactly in the axis of the shell ; whorls sixteen to eighteen, 

 rounded on the side, body whorl slightly subangulated below; 

 suture impressed ; umbilicus minutely perforate, and bordered 

 by a slight angle ; aperture irregular in outline, angnlated in- 

 ternally, above and belov/ ; outer lip but slightly expanded; 

 inner lip curved internally, and expanded so as to hide the um- 

 bilical region in part, most expanded in the middle, and in some 

 specimens distinctly subangulated at this point. Surface 

 sculptured by small longitudinal, slightly arched ribs ; color 

 light horn brown. 



Observations. — Tliis shell seems at first glance nearly a 

 miniature of U. Neivcomhiana, but has many more whorls, de- 

 spite its smaller size ; it also differs in many other less import- 

 ant details. Found in similar localities, and often associated 

 with that species. 



The present shell and U. Neivcojiibiana are without doubt 

 congeneric, and an examination of the animal of the latter shows 

 it to be a true Urocoptis. The former species, however, so 

 closely resembles the shell described by Adams and Angas as 

 Siibulina (sub. gen. CoeUaxis) Layardi, from South Africa, that 

 I am led to believe that these authors, in founding the sub-genus, 

 and in the reference of their shell to SuhiiUna, have been led 

 into error by external resemblances. Our shell difters from 

 Layardi in its smaller size, more slender form, and in the de- 

 tails of the mouth. 



