182 UMBRACULUM. 



The soft parts have been figured by Blainville, Gray, Eydoux 

 and Souleyet, and Gould. The locality of the single alcoholic spec- 

 imen figured by the first two authors is not known. The figures of 

 the Bonite voyage and the U. S. Exploring Expedition were drawn 

 from Sandwich Island examples ; and this form Pease proposes to 

 separate specifically from the " U. indica " under the name auran- 

 tium. The characters of the soft parts cited by him are useless, as 

 no adequate information on those of U. sinicum is extant, his com- 

 parison with the Bonite figures being fallacious on account of the 

 fact that those figures were drawn from Sandwich Island specimens. 

 He distinguishes the shells by the less marked radiating ribs and 

 color of the inside, which is " in the center dark chestnut-brown, 

 muscular impression yellowish, bordered by a concentric band of 

 chestnut-brown, outer edge yellowish. Length 5J, diam. 4 inches." 

 The animal " attains the size of 8 inches in length," and when liv- 

 ing is orange yellow. 



Hawaiian specimens before me differ slightly from typical U. sin- 

 icum in the obsolescence of the radial ridges externally. The body 

 is more depressed than in specimens of U. mediterraneum (judging 

 both by alcoholic examples), the tubercles of the surface are higher, 

 and the mantle edge has fewer, slenderer processes. 



Gould describes the Sandwich Island form as covered with prom- 

 inent tubercles of different sizes, growing smaller toward the mar- 

 gin, cream-colored, with olive shadings in the fissures, increasing 

 toward the margin, branchia? orange colored. 



U. CUMINGI Deshayes. PI. 73, figs. 86, 87. 



Shell large, irregularly patelliform, ovate, the vertex ex central, 

 bent toward the back and left side. White under a corneous, yel- 

 lowish epidermis, with radiating obtuse angles. Lower surface 

 with the central area subradiated with orange or chestnut, muscle 

 impression narrow, continuous, irregular. Length 120, width 90, 

 alt. 23 mill., or smaller. (Desk.). 



Island of Bourbon (Mail lard). 



Umbrella cumingi DH., Moll, de File Reunion, p. 52, pi. 8, f. 4, 

 5. 



Readily distinguished from U. indica by the form and the rela- 

 tive size of the colored middle area within. It is oval, quite regu- 

 larly obtuse at the ends. Outside covered by a yellowish corneous 

 epidermis, nearly identical with that of U. indica. This epidermis 



