22 AMERICAN MARINE CONCHOLOGY. 



Subgenus Admete, Kroyer. 

 Moller, Naturhist. Tidskr., iv. 88. 1842. 



Shell ovate, thin, covered with. an epidermis; spire acute, last 

 whorl ventricose ; aperture oval, chanelled anteriorly ; columella 

 with a few obsolete rudimentary folds ; outer lip thin, simple, 

 acute. 



This group appears to represent Cancellaria in the northern 

 seas in the same manner that Troplion represents Hurex, and 

 Bela certain species of Mangelia. 



2. C. VIRIDULA, Fabricius. Fig. 24. 



(Tritonium.) Fauna Grcenlandica, 402. 1780. 



Cancellaria buccinoides, Couthouy, Bost. Journ. Nat. Hist., ii. 105, t. 3, f. 3. 

 Cancellaria Couthouyi, Jay, Cat. 1839. 

 Admete viridula, Stimpson, Check Lists, No. 6. 



Shell oblong, longitudinally obscurely ribbed, spirally lined, 

 spire acuminated; whorls rounded, suture strong; aperture short, 

 smooth, columella obsoletely plaited; white, under a pale green 



epidermis. Ten to forty fathoms. 



Massachusetts to Arctic Ocean. 



Genus TKICHOTKOPSIS, Brod. & Sowb. 



Zool. Journ., iv. 373. 1826. 



Shell thin, ventricose, keeled, .umbilicated; aperture longer than 

 the spire, compressed into a partial canal in front ; epidermis 

 horny, rising into hairs at the angles of the shell ; operculum 

 horny, nucleus at one side. 



There are about a dozen species, principally of arctic distribu- 

 tion. 



1. T. BOREALIS, Sowerby. Fig. 25. 



Zool. Journ., iv. 373, t. 9, f. 6, 7. 1826. 

 T. costellatus, Couthouy, Bost. Journ. Nat. Hist. ii. 108, t. 3, f. 2. 



Shell ovate-rhomboidal ; whorls four, the last very broad, and 

 encircled by four or five, and the others by two prominent, fringed 

 ribs, and crossed by minute and regular elevated lines. Fifteen 

 to twenty fathoms. 



From Massachusetts northward, Northern British Coasts. 



