42 TRICHOTROPIS. 



LfBocochlls, Diinker and Metzger, has been referred to Tri- 

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

 monograph of the ftimily Cerithiidfe. 



Trichotropis has been monographed by : 



Sowerb}^, Thes. Conchyl., 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 ver^^ large, encircled by two 

 distant ciliated keels ; umbilicus rather large, with ciliated 

 margin; epidermis yellowish brown. Length, TS inches. 



Japan, Alaska, Grinnell Land. 

 T. Sowe7-byanus, Lesson, is a s3-non3'm, and T. tenuis, E. A. 

 Smith (fig. 43), is a monstrosity. 



Yar. ALTA, Dall. 



Whorls 4, with more elevated spire, aperture narrower and 

 smaller, umbilical excavation much narrower and smaller; solid 

 and strong. 



Plocer Bay, E. Siberia. 

 Var. 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. BOREALis, Brod. and Sowb. PL 7, figs. 44-48, 52, 59. 



Umbilicated ; whorls few, shouldered, and spirall}^ keeled, the 

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

 covered with a yellowish brown epidermis, haiiy^ on the ridges, 

 aperture often pink within. Length, 1 inch. 



Norther-n Europe, Greenland to Massachuselts, 



Arctic America, Japan. 



There are a number of synon^-ms, partl}^ in consequence of 



the great . variation in the development of the keels, much 



