1904.] NATURAL SCIENCES OF PHILADELPHIA. 27 



Hahajima, Ogasawara. Types No. 85,951, A. N. S. P., from No. 

 1,385 of Mr. Hirase's collection. 



Rissoina rex n. sp. PI. IV, figs. 42, 42a. 



Shell solid, the lower two-thirds slowly tapering, somewhat cylindric, 

 the upper third more rapidly tapering to an acute apex; not glossy; 

 white. Sculpture of regular longitudinal rounded ribs, as wide as 

 their intervals and about 19 in number on the penultimate whorl, and 

 not extending upon the base of the last one. These ribs are crossed 

 by numerous unequal fine spiral threads. Whorls 10, moderately 

 convex, parted by a deeply impressed suture, the last whorl swollen 

 behind the outer lip. Aperture small, ovate, vertical, hardly chan- 

 nelled below. 



Length 14, diam. 4.8 mm. 



Hirado, Hizen. Types No. 85,949, A. N. S. P., from No. 753 of Mr. 

 Hirase's collection. 



This large Rissoina seems to be rather abundant. With the type 

 lot there was a specimen of a reddish-brown color with a small white 

 basal tract and a light band above. The ribs are more numerous t 

 25 on the penultimate whorl, and there are 4 broad varices on the last 

 3 whorls, while the type has only 1 at the end of the last volution. The 

 shape is also less cylindric than in the type. More material is needed 

 to determine the status of this form. 



Rissoina materinsulae n. sp. PL V, figs. 43, 43a. 



Shell oblong-acuminate, the outlines of the spire convex; solid, white. 

 Sculpture of many small straight, crowded, rounded, low longitudinal 

 riblets, the intervals transversely striate. The apex is wanting, about 

 6 whorls remaining. These are slightly convex and separated by a 

 shallow, linear suture. The last whorl is swollen into a wide rounded 

 varix behind the outer lip, the fine riblets of the rest of the surface 

 being developed also upon it. The aperture is semioval, the thick outer 

 lip a little advanced below; columellar margin moderately concave, 

 truncate below by the shallow, rounded basal channel. 



Length 5, diam. 2 mm. 



Hahajima, Ogasawara. Types No. 85,976, A. N. S. P., from No. 

 l,390a of Mr. Hirase's collection. 



Rissoina (Rissolina) laevicostulata n. sp. PI. V, fig?. 44, 44a. 



Shell narrowly ovate-acuminate, regularly tapering from the last 

 whorl, white, with a red-brown blush on the back of the last whorl, 

 moderately solid. Sculpture of about 20 rounded, obliquely longitudi- 

 nal, slightly sinuous ribs about as wide as the intervals, both ribs and 



