138 



AMERICAN JOURNAL 



This genus is related to Tiedmannia, from which it differs in 

 the pendant body and absence of even an internal cartilaginous 

 shell. 



Type Corolla spectabills, n. s. 



Pinnoe broadly rounded, two small indentations in the upper 

 portion, giving it a trilobed appearance, rather than transverse, 

 translucent yellowish, speckled with black dots on the upper 

 margin ; crossed from one side to the other by arched, broad 

 bands of muscular fibre, which are reticulated by similar radi- 

 ating bands. A deep, broad sinus separates the pinnae from the 

 parts surrounding the mouth. The orifice of the latter is trum- 

 pet-shaped, situated in a transverse cleft of the membranes 

 which surround it and which are roundly produced on each side 

 of it like the lower portion of a pea-blossom. (Esophagus slen- 

 der, bright yellow. The neck, by which the body hangs, is con- 

 stricted, giving it a vase -like appearance. The intestines are 

 variously tinted with brown, purple and green. 



Lon. of body, *5 ; total Ion., 2-0 in. Width of pinnae, 1*8 ; 

 height of do., 1/1 in. 



Habitat— North Pacific Ocean, in lat. 42° 50' and lon. 147° 

 25'. July 22, 1866, W. H. Dall, Coll. reg. No. 307. 



This beautiful Pteropod is gregarious, as a number were taken 

 together at one haul of the towing net, but not on any other 

 occasion. A more detailed account of this and the other pelagic 

 Mollusks, obtained in the North Pacific by me, is in course of 

 preparation. 



Judging by Rang's figures, Cymbulia radiata and 'punctata, 

 Quoy and Gaimard, may possibly belong to this genus. 



LIMACINIDJE. 



LIMAOINA, Cuvier. 

 LlMACINA PACIFICA, n. S. 



Limacina pacifica, Dall., MSS. 1866. 



Pinnae arched above, rounded at the ends and deeply, widely 

 notched below. Pedal disk bilobed, rather large. These parts 

 translucent whitish. Sides of oral aperture painted with pink, 

 tentacles two, short, conical, obsolete. Viscera pink. Opercu- 

 lum absent. Shell with a band of brown following the suture, 

 otherwise hyaline, depressed of seven whorls, rather inflated, 

 especially the last, umbilicus small. Diam. Alt. 



This I have also compared with Atlantic specimens ; the shell 

 is more depressed, has a larger number of whorls, is smaller, 



