430 PLIOCENE MOLLTJSCA. 



1878. Trichotropis Kroyeri, Leche, K. Svensk. Vet.-Akad. Handl., vol. xvi, p. 47, pi. i, fig. 12. 



1887. Trichotropis Kroyeri, Tryon, Man. Couch., vol. ix, p. 44, pi. viii, fig. 61. 



1887. Trichotropis Kroyeri, Aurivillius, Vega Bxped., Vet. Jakt. Stockholm, vol. iv, p. 328, pi. xii, 



figs. 12, 13. 

 1901. Trichotropis Kroyeri, Friele og Greig, Norske Nordh. Exped. (Mollusca), pt. iii, p. 71. 



Specific Characters. — Shell small, thin, ovate-conical ; whorls 5, convex, not 

 carinated, the last tumid, much the largest; spire short, ending in a blunt point; 

 ornamented by spiral ridges with exceedingly fine longitudinal lines in the inter- 

 spaces and by inconspicuous lines of growth ; mouth pyriform, angulated above 

 and below; umbilical fissure wide and open; canal very short, pointed; outer lip 

 rounded. 



Dimensions. — Of Crag specimen, L, 8 mm. B. 6 mm. 



Distribution. — Recent .- Spitsbergen, Nova Zembla, Kara Sea, Behring Sea. 



Fossil : Waltonian Crag : Little Oakley (unique). Montreal 

 (Dawson). 



Remarks. — The small fossil here represented was found at Oakley. It agrees 

 more or less closely with the specimen figured by Leche (pp. cit.) except that it is 

 considerably smaller. 



T. Kroyeri is an arctic form which has not been hitherto reported from any 

 Pliocene horizon. Sir J. W. Dawson gives it with a ? as T. arctica, from a 

 Pleistocene deposit at Montreal, where he says it is very rare. 



Trichotropis insignis, Middendorff. Plate XLIV, fig. 39 ; var. Woodii, nov., 



fig. 40. 



1848. Trichotropis insignis, Middendorff, Mem. Acad. Imp. Sci., St. Petersb. [6], vol. vi, p. 436, pi. x, 



figs. 7, 8, 9. 

 1848-74. Trichotropis borealis, var. incrassata, S. V. "Wood, Mon. Crag Moll., pt. i, p. 67, pi. xix, 



fig. 11, 1848; T. insignis, 1st Suppl., pt. ii, p. 207, 1874. 

 1856. Trichotropis insignis. Carpenter, Rep. Brit. Assoc. (Cheltenham), pp. 217, 223, 328. 



Specific Characters. — Shell thin and fragile, ovato-turreted ; whorls 6, carinated, 

 flattened above, with a wide sloping shelf below the suture, the last much the 

 largest ; ornamented by rather rough irregular spiral ridges, reaching the suture, 

 two or three of them more prominent than the others, with finer ones in the 

 interspaces and upon the shelf, together with numerous indistinct costce in the lines 

 of growth ; spire short, small, rapidly diminishing upwards towards a blunt spire ; 

 suture deep and channelled ; mouth very large and wide, greatly expanded ; outer 

 lip thin, rounded, forming with the inner lip a continuous and glazed peristome; 

 umbilicus long and narrow. 



Dimensions. — L. 16 mm. B. 12 mm. 



