116 AMERICAN JOURNAL 



This little species is about one-half the size of the preceding, 

 yet has as many whorls. The latter are rounded though not 

 inflated, not flattened as in the last. The nucleus also differs. 

 A. tuberosa is conoid, this is regularly fusiform. I have not seen 

 any specimens of tuberosa, with exactly similar zigzag lines, such 

 as three of my specimens of aurantiaca exhibit. 



NlTIDELLA ELEGANS, n. S. 



Shell small, smooth, polished, solid, of eight whorls, which are 

 very slightly convex, though not flattened. Suture appressed, 

 not strongly marked. Canal short, outer lip sharp, slightly 

 Urate inside, straight, or hardly sinuated. Columella smooth, 

 with a thin callus, outside of which a few faint stride pass round 

 the canal on the anterior part of the last whorl. Shell subulate, 

 acutely pointed ; nucleus yellowish white, pointed ; first four 

 whorls with a brownish yellow ground reticulated by white dots, 

 an ornamentation which also appears on the anterior part of the 

 last whorl. Markings in general consisting of transverse, alter- 

 nate, dark red brown and white bars, slightly fluctuated on the 

 last whorl. The white and brown rectangular bars, not being 

 continuous from one whorl to another, give the shell a tessalated 

 aspect. Lon. -28, iat. -11 in. Defl. 33°. 



Habitat, Panama ; among a large number of minute shells 

 collected by the late Thos. Bridges, F. L. S., one specimen 

 occurred. 4 



This shell is readily distinguished by its subulate form, pecu- 

 liar and beautiful markings, and proportionally less solid and 

 heavy texture, from the well-known N. cribraria. It has as 

 many whorls as that species, but does not reach a quarter of the 

 size. It does not resemble any of the other species from the 

 "coast, but may be compared with Columbella dichroa, Sby., from 

 the West Indies. 



RISSOID^E. 



Alvania purpurea, n. s. 



Rissoina? ? purpurea, Dall, MSS. 1866. 



Shell small, of four rounded whorls, rather pointed. Sculp- 

 ture of six or seven revolving ribs, on the last whorl, only two 

 appearing on the second whorl ; apical whorl smooth. These 

 ribs are crossed by about twenty longitudinal riblets, which do 

 not pass the second revolving rib on the last whorl. On the 

 antepenultimate whorl they reach from suture to suture, and are 

 conspicuously angulated at their intersections with the two 



