526 PROCEEDINGS OF THE ACADEMY OF [August, 



spiral lamella is seen in C. subttculus to be much lower than in 

 C. tau. This is well shown in the views of the interior from 

 behind, fig. 39 (subaculus) and fig. 43 (tau). In both species the 

 subcolumellar lamella is noticeably dilated where it passes the lower 

 palatal plica, shown in Ihe same figures. C. digonoptyx is a more 

 strongly striate shell, with the inferior lamella much more closely 

 approaching the superior. 



This species was collected at Nagasaki in numbers by Prof. Dr. 

 J. J. Rein, and at first (1878) identified by Prof. Boettger as 

 C. aculus of Benson, a species originally described from Chusan. 

 Subsequently (1879) Boettger recognized that the Japanese form 

 was distinct from Benson's Chinese species, but trusting to sup- 

 posedly authentic specimens labeled C. proba A. Ad. in Dohrn's 

 collection, he substituted this name for the Nagasaki species. This 

 determination, however, cannot stand, being contradicted by the 

 terms of A. Adams' diagnosis of C. proba. He describes that 

 shell as 5^ lines (11 mm.) long, with eight whorls, " lamella 

 supera valida, connpressa," whereas the Nagasaki species under 

 discussion is larger, with about 10 whorls, and a remarkably low, 

 weak and inconspicuous superior lamella. Moreover, the locality of 

 C. proba is far removed from Nagasaki, being in Awa province, 

 east of the entrance of the Bay of Yeddo. Whatever C. proba 

 may prove to be, it is surely not closely related to C. aculus. 



Under these circumstances it becomes necessary to rename the 

 Nagasaki species ; and in so doing I have considered it best to give 

 a new description, in order that there may be in future no uncer- 

 tainty about the exact form intended. 

 Clausilia rowlandi n. sp. Pi. XX VIII, figs. 28, 29, 30. 



Shell fusiform- turrit e, the spire slender, nearly straight-sided, 

 tapering to a small apex ; light-brown. Surface finely and rather 

 sharply striate. Whorls 10, rather strongly convex, especially 

 just below the suture, the last shortly free in front. Aperture 

 narrowly piriform, the upper margin slightly sinuate at the position 

 of the superior lamella, the well-marked sinulus a little retracted. 

 Peris tome white, thickened, expanded and reflexed. Superior 

 lamella merely a small cord, terminating in a rather wide thicken- 

 ing of the margin of the peristome, continuous inside with the 

 spiral lamella, which penetrates nearly to the middle of the ventral 

 side. Inferior lamella receding, becoming high within, approach- 

 ing the superior lamella, shorter within than the spiral lamella. 



