118 PROCEEDINGS OF THE ACADEMY OF [March, 



double cone, ' ' and the greater prominence of several spiral cords or 

 angles above and below. Iwakawa has abundantly proven that 

 this form intergrades perfectly with the typical V. japonicus a fact 

 manifest in the series before me. He holds also that it intergrades 

 with the form called ' ' P. sclateri ' ' by Kobelt, but which is far 

 from being the typical V. sclateri of Frauenfeld. He also gives 

 reasons for believing that this carinate form " represents the ances- 

 tral species whence the several varieties have arisen." It seems to 

 be confined to the northern third of Nippon, so far as existing data 

 show. Types of var. iwakawa are from Furukawa, Rikuzen, No. 

 80,639 Coll. A. N. S., from No. 61 of Mr. Hirase's collection. 



I have not yet seen specimens of the form called sclateri by 

 Iwakawa. It occurs in the same area as var. iwakawa, and so far 

 as we know not in southern Nippon, where the true V. sclateri 

 and where Kobelt 7 s sclateri live. 

 Viviparus histricus (Gould). Pi. IX, fig. 5. 



Paludina histrica Gld., Proc. Boston Soc. N. H., VII, p. 41 (June, 



1859); Otia Conch., p. 106. 

 f Paludina nitens Reeve, Conch. Icon., fig. 59 (April, 1863). 



The shell is umbilicate, pyramidal, brownish-green, and glossy 

 when clean. There are no puncture-lines, though faint spiral 

 striae exist. The whorls are carinate at the periphery, the keel 

 usually projecting above the sutures, but reduced to a mere low 

 cord on the last whorl. A well-grown specimen measures, alt. 31, 

 diam. 21 mm. Figured specimen is from Kagoshima, Satsuma. 

 Viviparus sclateri Frauenfeld. PI. IX, fig. 4. 



V. sclateri Ffld., Verh. zool.-bot. Ges. Wien, XV, 1865, p. 531, PL 



22, upper figures on left side. 

 f Paludina ingallsianus Reeve, Conch. Icon. , XIV, PI. 7, fig. 89 a, b 



(1863). 

 P. ingallsiana Reeve, Kobelt, t. c., p. 124, PI. 10, fig. 14-18; PL 11, 



fig. 2. 

 P. ingallsiana Reeve, Iwakawa, t. c., p. 86, PL 5, figs. 5-7 (not 



typical). 



f P. sclateri Kobelt, t. c., p. 121, PL 11, fig. 3. 

 Not P. ingallsiana Lea, 1856 ! 



A pyramidal, brownish species, with strongly angular periphery 

 and several low angles above it. The shell attains a large size, the 

 specimen figured measuring alt. 45, diam. 30 mm., though eroded 

 above. 



V. sclateri is, perhaps, a variety of V. histricus, but as I have 

 not seen specimens connecting them, I allow it to stand here as a 

 species, pending fuller information. 



