2 THE NAUTILUS. 



Length 7.2, greatest diam. 3 mm. (old specimen, 5 J whorls 

 remaining). 



Length 8.2, greatest diam. 3 mm. (less eroded specimen, 7J 

 whorls remaining). 



Length 6.6. greatest diam. 2.6 mm. (younger specimen, 6^ 

 whorls remaining). 



This species is related to Blcmjordia japonica A. Adams, of 

 Sado Island, both having a well-developed varix behind the 

 lip; but the Sado shell has a higher varix, and a much more 

 rapidly tapering spire, the later whorls much wider. A speci- 

 men of B. japonica 7.3 mm. long is 4.3 mm. in greatest diam- 

 eter. It is usually larger, about 8 mm. long, after having lost 

 a whorl or two at the tip in the adult stage. 



Blanfordia is probably distributed over the whole of the main 

 island of Japan, Sado, Kyushu and southern Yesso. The fol- 

 lowing species are known to me by many specimens of all of 

 them sent by Mr. Y. Hirase and also from other sources: 

 a. Outer lip of the shell strengthened by a rounded varix. 

 b. Shell slender, slowly tapering, the greatest diam- 

 eter less than half the length. B. nosophora 

 (Robson) Kyushu. 

 bb. Shell stout, conic, the greatest diameter more than 

 half the length. B. japonica (A. Ad., 1861) 

 Sado. 

 aa. Outer lip of shell without any external varix. 



6. Larger, the length 8 or 9 mm. B. bensoni (A. Ad., 

 1861) Hokkaido. 

 bb. Smaller, the length 6 to 6.5 mm. B. simplex Pils., 

 1902, Uzen, etc. 

 I have a smaller form than B. simplex, with the apex perfect, 

 from Izumo and Omi, but as there are very few specimens, I do 

 not feel sure that it is distinct from B. simplex; especially since 

 a snail which seems to be not specifically distinct from simplex 

 has been sent by Mr. Y. Hirase from Kajima, Satsuma (his 

 no. 406). 



Erosion of the early whorls in fresh-water gastropods seems 

 to be consequent upon extensive parasitization of the Hver. It 

 may be that on breaking down of the peripheral (terminal) cells 



