42 TRICHOTROPIS. 



Lseocochlis, Danker and Metzger, has been referred to Tri- 

 chotropidae by Dr. von Martens. I shall include it in my 

 monograph of the family Cerit.kiidae.- 



Trichotropis has been monographed by : 



Sowerby, Thes. Conchy 1., iii, 321. 12 species. 

 Sowerb}', Conch. Icon., xix, 13 sp., 1874. 



Genus TRICHOTROPIS, Brod. et Sowb., 1829. 

 T. BICARINATA, Brod. and Sowb. PI. 7, figs. 42, 43. 



Rather thin, whorls few, the last very large, encircled by two 

 distant ciliated keels ; umbilicus rather large, with ciliated 

 margin ; epidermis yellowish brown. Length, 1-5 inches. 



Japan, Alaska, Grinnell Land. 



T. Sowerby anus, Lesson, is a synonym, and T. tennis, E. A. 

 Smith (fig. 43), is a monstrosity. 



Yar. ALT A, Dall. 



Whorls 4, with more elevated spire, aperture narrower and 

 smaller, umbilical excavation much narrower and smaller ; solid 

 and strong. 



Plover Bay, E. Siberia. 

 Yar. srECTABiLis, Dall. 



Whorls 5, with elevated spire ; columella narrow, waved, not 

 truncate, straight, not arched as in the two preceding forms, its 

 outer edge strongly elevated ; umbilicus a mere groove ; whorls 

 much flatter above and below, the last wide out of proportion to 

 the spire, the second carina apparent on all the whorls ; aperture 

 sharply pointed below, painted with sea-green within and on the 

 columella. 



Near Plover Bay, E. Siberia. 



T. BOREALTS, Brod. and Sowb. PI. 7, figs. 44-48, 52, 59. 



Umbilicated ; whorls few, shouldered, and spirally keeled, the 

 last with two to five strong keels, varying in development; 

 covered with a yellowish brown epidermis, hairy on the ridges, 

 aperture often pink within. Length, 1 inch. 



Northern Europe, Greenland to Massachusetts, 



Arctic America, Japan. 



There are a number of synonyms, partly in consequence of 

 the great variation in the development of the keels, much 



