THE NAUTILUS. 19 



that I refer this form to P. californim : it might just as well be re- 

 garded as a distinct species. But for that there will be time if no 

 intermediate and connecting forms be found. 



It will be of special interest to examine and compare the soft parts 

 of all these varieties or forms, anatomically as well as to the mode 

 of life. 



Some conchologists may consider it to be useless or oven worse to 

 apply varietal names to the forms described above ; but we must try 

 to arrange them systematically as naturally as possible, according to 

 their relations among themselves and with kindred species ; and for 

 that purpose Ave must name them. And it is also for convenience ; 

 is it easier to say, in citing: " that variety of P. caltfornica inhabit- 

 ing Santa Catalina and San Clemente Islands, much smaller than the 

 .type, with lower whorls, lighter coloration, relatively coarser striation, 

 and xoell formed lamellce," than simply designating it by a name? 

 Pupa Dalliana .<p. nov. 



Shell conic or ovate-conic, of greenish-horn color, transparent, finely 

 irregularly striate in the lines of growth, polished; whorls 41, well 

 rounded, with deep suture, rather rapidly increasing, the last occupy- 

 ing about I of altit., towards the aperture somewhat ascending on the 

 penultimate. Aperture lateral, somewhat oblique, subovate with 

 just jierceptibly flattened i)alatal margin ; margins approximate, the 

 ends protracted ; peristome shortly but decidedly expanded, with a 

 very fine thread-like lip near the margin, the same continuing as a 

 very fine callus on the apei'tural wall inside of the line connecting 

 the ends of the margins ; palatal wall quite simple ; no lamella\ 



Alt. 1.2; diam. 1. 3 mill. 



This form has been collected by Mr. Hemphill near Clear Lake, 

 Lake Co., Cal., and I propose to name it in honor of Mr. Wm. H. 

 Dall. The specimens before me were fifteen, fi*esh, remarkably uni- 

 form in their Avhole appearance ; all were more or less covered with a 

 dark brown, hard crust of slime and dirt, generally thickest around 

 the aperture. Doubtless this coating is done " purjjosely " by the 

 animals, as in many other species also. When cleaned, it shows 

 about the size and shape of a well-grown Vertigo ovata, Say, but by 

 a good eye or under a glass is at once recognized as something else, 

 by the rounded aperture and the absence of lamellae. 



