44 ACM^EA. 



A. SCHRENCKII Lischke. PI. 2, figs. 21, 22, 23, 24. 



Shell elliptical, much depressed, rather thin. The apex is 

 situated between the front sixth and eighth of the shell's length ; 

 posterior slope convex, its curve generally higher than the apex. 

 Sculptured with very fine, unequal thread-like riblets, which are 

 very closely granose ; of an olive-ashen color, variously marbled 

 with blackish-olive. 



Inside light blue with a broad blackish border and an ill-defined 

 dark chestnut central area. 



Length 31, breadth 22-24, alt. 4-6 mill. 



Ojima and Nagasaki, Japan. 



P. schrenckii LISCHKE, Mai. Blat. xv, p. 220 ; Jap. Meeres-Con- 

 chyl. I p. 107, t. 8, f. 1-4. Tectura schrenckii DKR., Ind. Moll. 

 Mar. Jap., p. 155. 



My description is drawn from typical specimens collected at 

 Ojima by Mr. Frederick Stearns. The species is variable in mark- 

 ings, the mottling sometimes being converted into stripes obliquely 

 radiating and curving from the central dorsal region. It is closely 

 allied to P. concinna, but is of a longer elliptical outline, is more 

 depressed, and the granulation is finer. Still, I am disposed to 

 believe that the two will be united when fuller collections are made. 



A. CONCINNA Lischke. PL 2, figs. 12, 13, 14, 15, 16, 17. 



Shell oval, rather thin ; apex at the front fifth or sixth of the 

 shell's length ; posterior slope convex. Surface sculptured with 

 close fine unequal riblets, finely and distinctly granulose ; of a uniform 

 blackish-olive shade, or variegated with olive, green or brown on a 

 very light green ground. 



Inside light blue, with a wide dark or spotted border, and an ill- 

 defined central darker tract. Length 24, width 20, alt. 6 mill. 



Yokohama to Enofhima, Japan. 



P. concinna Lischke, Mai. Bl. xvii, p. 25 ; Jap. Meeres-Conchyl. 

 ii, p. 98, t. 6, f. 1-6. Tectura coneinna DKR., Ind. Moll. Mar. Jap. 

 p. 154. P. granostriata SCHRENCK, Amurl. Moll. t. 14, f. 1-3. 



Closely allied to A. schrenckii, probably a variety of that species, 

 but rounder, more elevated, more distinctly granulose. These 

 Japanese forms have much in common with A. scabra of the Cali- 

 fornian coast, but they are abundantly distinct in sculpture, the 

 position of the apex, and the general tone of coloring. 



