280 SUBEMARGINULA. 



S. aspera Gould. PI. 41, figs. 40, 41, 42, 43. 



Four principal posterior ribs double ; about 10 primary ribs. 



Shell oval, elevated or depressed, apex subcentral ; sculptured 

 with about 10 principal ribs, four of the -posterior ones double or 

 divided by a median groove ; interstitial riblets irregular, variable 

 in number. Concentric striae nearly obsolete in adults, fine and 

 obsoletely prickle-scaly in the young. Color grayish-white or 

 chocolate-brown between the larger ribs. Inside white, with or 

 without dark radiating stripes ; no distinct mushroom-shaped pat- 

 tern inside the muscle-scar; anterior groove very short, but the 

 notch rather deep; margin thick, obsoletely, irregularly crenulated, 

 the marginal denticles about 50 in number. 



Length 20, width 14, alt. 8 mill. 



Length 18, width 13, alt. 13 mill, (most elevated seen). 



Fiji, Viti and Philippine Is.; S. Australia f 



E. aspera Gould, Proc. Bost. Soc. N. H. ii, p. 154, 1846 ; U. S. 

 Exped. Sh. p. 372, atlas, f. 493. — E. cinerea Gld., I. c. p. 155 : atlas 

 to Exped., f. 494. — Subemarginula crassilabrum A. Ad., P. Z. S. 

 1851, p. 91.— Sows., Thes. p. 217, f. 79.— ? S. sculptilis Ad., P. Z. 

 S. 1851, p. 92. 



I have considered the double posterior ribs, short sulcus, etc. to 

 l)e diagnostic points of a species; and have united certain described 

 forms which agree in these characters. The type of aspera (pi. 41, 

 figs. 40-43) is a young shell. E. cinerea Gld. (pi. 41, figs. 28-31) 

 from Fiji Is. may be distinct. It is thinner, and has a mushroom- 

 shaped pattern inside, but the posterior ribs are double. E. crassi- 

 labrum Ad. (pi. 29, fig. 16), and E. ossea Gld. (pi. 41, figs. 22-25) 

 from the Fiji Is. do not seem to differ. 



S. sculptilis A. Adams. PL 29, fig. 19. 



Oval, obliquely conical, whitish, radiately maculated with green ; 

 summit subcentral, deeply declining backward ; corrugated by 

 radiating ribs, the interstices beautifully punctate-clathrate ; prom- 

 inent anterior rib crenulated ; margin of aperture undulated and 

 crenulated, rounded behind, truncated and sinuous in front, the 

 sinus produced into a channel inside. Clathrated as in E. Panh iensis, 

 but not so elevated and more compreesed at the sides, with a brown 

 marginal spot between each of the larger ribs. (Ad.) 



Calapan, Island of Mindoro, Philippines. 



Subemarginula sculptilis Ad. P. Z. S. 1851, p. 92. — E. sculptilis 

 Sowb. Thes. p. 218, f. 89. — E. sculptilis Sowb. in Conch. Icon. f. 53. 



