40 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Trichotropis costellata Couthouy, 1838 
Boston Journal of Natural History, 2:108; PI. 3, fig. 2. 
T. testa ovata, turrito-acuta, fuscescente, epidermide foliacea luteo- 
albida testa; spira canaliculata; anfractibus costis 5 rotundatis instructis; 
apertura ovali, lutescente; labro costis indentato; columella arcuata, 
albescente. (Couthouy.) 
Shell ovate, acutely turreted; spire elongated; whorls six, the lowest 
ventricose and larger (longer) than all the rest together, having four or 
five and sometimes even six, revolving prominent, rounded costae, with in¬ 
tervening striae; the largest of these costae borders the superior portion 
of the whorls, forming distinct angulations; numerous fine longitudinal 
striae, not interrupted by the ribs, cover the whole shell; color a dull 
yellowish or brownish white; aperture oblong-oval; narrowed and slightly 
channeled at the base; lip continuous at its superior extremity, and dis¬ 
tinctly indented by the costae; columella whitish, arcuated, with a slight 
projection near its lower third, and abruptly compressed near its base, 
which inclines to the right, and forms a sharp angle with the outer lip; 
umbilicus slight, and bordered externally by a strongly marked imbricated 
ridge. Interior a light brown. Epidermis a dirty whitish yellow, thick, and 
foliated or laminated by its successive growth, which traversing the 
costae, gives the shell quite a clathrate appearance. At each stage of the 
increment, the epidermis is produced upon the costae into two or three, 
stiff, corneous filaments or bristles, which when the shell is wet, cause it to 
appear covered with short hairs; the same setae are apparent though less 
conspicuous upon the ridge bounding the umbilicus. (Couthouy.) 
Type in Couthouy Collection. Type locality, deep water Massachusetts 
Bay. 
Range. Arctic Seas, Bering Sea, Aleutian Islands, and Queen Char¬ 
lotte Islands, British Columbia. Circumboreal. 
Trichotropis cancellata Hinds, 1843 
Proceedings, Zoological Society of London, 17. Zoology of the Voyage of H. M. S. 
Sulphur, Molluscae, PI. 11, figs. 11, 12. 
Tri. testa pyramidata; spira elevata; anfractibus subrotundis, ultimo 
ventricoso, costellis seto, crenulatis, ciliatis cincto; umbilico parvo; colu¬ 
mella tenui, arcuata; apertura rotunda, antice acuta. (Conchologia 
Iconica.) 
Shell pyramidal; spire elevated; whorls rather rounded, last whorl 
ventricose; encircled with eight crenulated, ciliated ribs; umbilicus small; 
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