to Captain J. Bollons for his courtesy and the troubl he has taken to procure the specimens.

The following is a description of the very remarkable new species:—

Placostylus bollonsi, n. sp. Plate XXV, figs. a, b, c.

Shell large, oblong-cenic, with a very obtuse apex, rimate, fairly solid, axially closely striate, brown, peristome simple. Sculpture: The first 3 whorls are finely and regularly axially costate and mostly not punctate; the 3rd and sometimes the 4th and part of the 5th whorl distinctly broadly plicate at the suture above; the following whorls are densely wrinkle-striate, the striæ of unequal strength, slightly oblique and crossed by distant spiral striæ, which are mostly obsolete upon the base. Some examples show a secondaryaxial sculpture on the 4th and 5th whorl, consisting of strongly oblique costæ, which are directed forwards, and reticulate the primary axial sculpture, forming a more or less distinct network. On the last 2 whorls a distinct narrow groove is margining the suture below. Colour yellowish-brown, with numerous narrow blackish-brown streaks on the lower whorls, the apical whorls usually denuded and flesh-coloured; peristome white, aperture purplish-red within;a whitish narrow subsutural border is sometimes present, but it is much less conspicuous than in P.hongii and very often wanting. Epidermis brown, thin, slightly shining. Spire elevated-conic, with a very blunt apex, 1 ¼ to 1 ½ times the height of the aperture; outlines very slightly convex. Protoconch of 3 convex whorls, the nucleus with a raised inner carina. Whorls 6 ½, the first few but little descending, lightly convex; base flatly rounded. Suture not deep, somewhat uneven, margined below on the lower whorls. Aperture vertical, pyriform, angled above, broadly rounded and somewhat angled towards the pillar below. Peistome continuous; outer lip not expanded and not much thickened, rounded and smooth, rarely with very slight indications of denticles within. Basal lip slightly expanded, smooth or with a few indistinct notches. Columella oblique, lightly concave, indistinctly folded above; inner lip not broad, with a well-marked rim forming the contmuation of the basal lip; very rarely a few small tubercles may be found on the lower partof the parietal wall, but usually it is quite smooth. The umbilical fissure is always small.

Diameter, 40 mm.; height, 91 mm. Type.

Diameter, 43 mm.; height, 99 mm. One of the largest specimens,

Animal black, irregularly and coarsely granular, the granules arranged in longitudinal rows on the back, sloping on the sides, a band of squarish and large granules along the pedal margin.

Anterior tentacles short, ommatophores distant, long, granular, with very broad bases. Foot broad, narrowly rounded behind. Mantle margin even, with a fold on the under surface in front of the respiratory orifice. Genital orifice behind the right ommatophore.

Jaw (fig. 1) arcuate, attenuated at the ends, irregularly striated by infoldings of the membrane.

Radula (fig. 2.) tongue-shaped, of about 130 transverse rows of teeth, which are nearly straight, forming a very obtuse angle, salient-posteriorly. Formula of radula: 20. 30. 1. 30. 20. The central tooth elongated, with a long and broad mesodont and a low and broadly rounded mesocone; usually there are two minute side-susps present. Lateral teeth, numbering about 30, with a very broad rounded mesodont, the mesocone short and broad; there is no endodont, but the ectodont is distinct, narrowly rounded, bearing a minute cutting-point. The marginals are narrower and with two cutting-points; towards the margins they are getting very narrow and indistinct, and it is impossible to exactly ascertain their number.

Reproductive Organs (fig. 3).—The male organ is very large, with the retractor muscle at its apex and the walls very thick. The vas deferens enters near the apex, and it is free only for a very short distance at the base. The albumen-gland is large. The most remarkable feature is the absence of a receptaculum seminis, which is present in P.hongii.

Remarks.—The teeth of the radula differ somewhat from those of P. hongii; in the latter the central tooth has no side cusps, the transition teeth between laterlas and marginals are getting tricuspidate, and most of the marginals show the same character. There is no difference in the reproductive organs of the two species except the absence of the spermatheca in P. bollonsi, and I found it to be absent in four specimens which I dissected.