FISSURELLA. 161 



F. RUGOSA Sowerby. PI. 31, figs. 21, 22. 



Shell oblong, the outline generally angular, narrower in front, 

 depressed ; summit in front of the middle. Hole variable in size 

 and shape, oval or oblong, its sides vertical, not noticeably contracted 

 in the middle. 



The outline is very variable and irregular, usually angled ; rather 

 depressed; rather thin ; varying from red to white in color of the 

 outside; sculptured with numerous unequal, more or less nodulous 

 radiating riblets. Inside pale green, the callus encircled by a 

 slightly darker line or not. Border irregularly toothed and cren- 

 ulated. 



Length 30, breadth 20, alt. 6J mill. 



Length 27, breadth 17, alt. 7 mill. 



Mazattan to Gallapagos Is. 



F. rugosa SOWB. Conch. Illust., f. 51. REEVE, Conch. Icon., f. 

 56. SOWB. Thes. Conch, iii, p. 189, f. 46, 47. CARPENTER, Maz. 

 Cat., p. 215. F. chlorotrema and F. humilis MENKE, Zeitschr. f. 

 Mai. 1847, p. 186. ?-F. viminea MKE. Zeitsch. 1851, p. 131, (not of 

 Rve.) 



The ribbing of this species is extremely variable, but generally 

 more irregular than in F. virescens. The orifice is more anterior 

 than in that species. 



F. RUBROPICTA Pilsbry. PI. 36, figs. 34, 35, 36. 



Shell varying from ovate to elliptical, conical, the summit a 

 little in front of the middle, sculpture consisting of rather rude 

 radiating riblets alternately larger and smaller. Dorsal orifice 

 oblong, each of its sides a little contracted and bidentate, becoming 

 smaller as it penetrates ; its length measured inside, contained 8 to 

 10 times in the length of the shell. Inside greenish, stained with 

 crimson inside of the muscle-scar, the perforation- callus green. 



The form is rather straightly conical ; surface dull, lusterless, cor- 

 roded, the sculpture being entirely effaced on the earlier portion of 

 adult shells ; ribltts uneven, unequal. Color on the corroded sur- 

 face greenish, painted on the lower part with narrow black rays. 

 These rays are far more prominent on young shells. The inside is 

 of a delicate green shade, fading to white at the border, the distinct- 

 ly impressed muscle-scar white, area inside the muscle-scar of a deep 

 crimson, or crimson and white, the hole-callus green, oval and dis- 

 11 



