1902.] NATURAL SCIENCES OF PHILADELPHIA. 527 



Subcolumellar lamella immersed, visible in an oblique view in the 

 aperture. Principal plica visible in the throat, extending past the 

 middle of the right side. Upper and lower palatal plicce quite 

 small, no lunella between them. 



Length 13.5, diam. 2.7 mm. 



Clausilium wide below, somewhat thickened at the apex, but 

 angular there, almost mucronate, by reason of an excavation of the 

 palatal side near the apex. The margins converge somewhat up- 

 ward, and it is excised on the columellar side of the filament. 



Garukawa, 10 miles from Sapporo, Ishikari, island of Yesso; 

 collected by Mr. Paul Rowland, and communicated to me by Mr. 

 Addison Gulick. 



Similar to C. subaculus in the low, cord-like superior lamella 

 continuous with the spiral lamella, but conspicuously distinct by its 

 narrowly pear-shaped aperture, more slender contour, the reduction 

 of the palatal plicae and the angular apex of the clausilium. 

 C. monelasmus, of Ojima province, Yesso, is a smaller species with 

 no superior lamella, there being only a marginal thickening of the 

 peristome in its place. 



The shape of the mouth readily distinguishes this from all 

 Japanese Euphcedusce. The clausilium is also characteristic, no 

 other Japanese Euphcedusa having it subangular at the apex. It 

 is named for Mr. Paul Rowland, who found the specimens and sent 

 them to Mr. Addison Gulick. 

 Clausilia tan Boettger. PL XXVIII, figs. 36, 37, 43, 44, 45. 



Boettger, Clausilienstudien, p. 58, footnote (1877); Jahrb. d. d. 

 malak. Ges., V, p. 46, PL 3, fig. 2. Kobelt, Fauna moll, extramar. 

 Jap., p. 70, PI. 8, fig. 18. 



The shell is finely striate, becoming costulate-striate on the back 

 of the last whorl, as in C. subaculus. The aperture is widely piri- 

 form, the upper margin distinctly sinuate at the position of the 

 superior lamella. The superior lamella is small, but decidedly 

 higher than in C. subaculus. The principal plica is long, extend- 

 ing inward beyond the lunella. The upper palatal plica is quite 

 long, united in the middle with the lunella, which is low or inter- 

 rupted in the middle, and curves inward below, terminating in a 

 nodular lower palatal plica. The whole structure, as seen from the 

 inside, has been aptly compared by Boettger to the Greek letter r. 

 The palatal folds show whitish on the outside. 



Length 12^-1 5J mm., diam. 3 3J mm. 



