142 THE NAUTILUS. 



what irregular striation, also on top of the beaks, shining ; color yel- 

 lowish to brownish horn; shell thin; translucent ; muscle insertions 

 slightly marked ; hinge rather short, slightly curved, tine, plate nar- 

 row ; the right cardinal tooth little curved or almost straight, thin; 

 the left inferior, short, slightly curved, the superior longer, rather 

 posterior and curved down at the posterior end ; lateral teeth fine, 

 the outer ones in the right valve quite small, those in the left valve 

 with short sharp cusps ; ligament small. 



Size : long. 5.3, alt. 4.5, diam. 3.4 mill, (largest specimen, long. 

 4.6, alt. 4, diam. 3.2 mill, and probably full grown.) 



Habitat : Lake Michigan, off New York Point, in deep water, 

 dredged by Mr. Bryant Walker, at 24 meters. 



The present Sphairium ranges under the group Corneola, with 

 Sph. rhoiitboideuin Say and uccidentale Pr., but is quite distinct from 

 both, not only by its small size ; from the former it is distinguished 

 by its well-rounded anterior part, from the latter, by its broader, less 

 prominent beaks and the oblique posterior end. It has some resem- 

 blance, in shape, with some forms of Spit, corneum Lin. of Europe, 

 but is very much smaller, its beaks are somewhat different and so is 

 the surface appearance. 



The specimens were first seen in November, 1894, and then re- 

 garded as representing a new species, and named in honor of Mr. 

 Bryant Walker, the indefatigable scientist and collector to whom we 

 owe so much conchological knowledge. 



A NEW PINNA FROM CALIFORNIA. 



P,Y WM. II. DALL. 



No species of the Pinnidce has hitherto been known from Cali- 

 fornia, or reported from any point more northerly than the Gulf of 

 California on the Pacific coast. It was therefore a surprise when I 

 received from Mr. and Mrs. Oldroyd a specimen taken alive by fish- 

 ermen in 25 fathoms, San Pedro Bay. This is rather an excep- 

 tional depth for a species of its solid and heavy character, the deep 

 water Pinnida; usually belonging to the small, delicate and spinose 

 forms, and the coarse imbricate species being more commonly found 

 gregariously, at no great distance below low water mark, where their 

 sharp edges have often been referred to as injurious to small boats 

 landing in the shallow water. The present form belongs to the genus 



