1917.] NATURAL SCIENCES OF PHILADELPHIA. 173 



of this species. Belongs to the section Apicularia of Tryon's arrange- 

 ment. 

 Bissoa (Alvania^ proavia n. sp. 



The shell is imperforate, rather plump, conic; first 2| whorls are 

 smooth, convex, and form a somewhat acuminate summit. Following 

 whorls have latticed sculpture of rather narrow vertical ribs, which 

 pass over the periphery but are obsolete over most of the base, 

 crossed by spiral cords a little narrower than the ribs, and forming 

 small nodes at the intersections. On the penult whorl there are 

 three spiral cords, the upper one at the shoulder. On the last whorl 

 there are six spiral cords, the second from above forming the peri- 

 phery, the lower two smooth, the others passing over ribs. Some 

 very minute spiral striae are visible in the intercostal spaces. The 

 aperture is nearly circular, the lip strengthened bj^ a strong varix. 



Length 1.35, diam. 0.9 mm.; 5 whorls. 



Type No. 3169, A. N. S. P. 



This species stands close to Rissoa lipeus Dall,- but it differs by 

 the acute apex and details of sculpture. 

 Hipponix otiosa n. sp. 



The shell is oval, obliquely conic, with the apex curving backward 

 nearly over the posterior margin. The apical portion sits cap-like 

 at the summit, and is probably smooth, though somewhat worn, the 

 original surface being mostly removed. The later growth is rudely 

 ribbed radially with 14 ribs in a young specimen 5 mm. long, 

 18 in the largest specimen, about 9.3 mm. long. The ribs are wide, 

 sculptured with rather rough growth-lines, and near the periphery 

 with coarse radial striae. The border is scalloped by the ribs. 



Length about 9.3, Avidth 8, height 5.5 mm. 



Type and two other specimens are No. 2887, A. N. S. P. 

 Natica finitima n. sp. 



The shell resembles N. canrena in shape. The narrow and short 

 spire is rather acute, of 5 convex whorls. The suture is very narrowly 

 channelled; last whorl very convex throughout. Umbilicus is formed 

 as in canrena except that the spiral pillar is decidedly smaller and 

 terminates in a much smaller columellar callus. Parietal callus- 

 is heavy. The surface shows light growi;h-lines, some of which are 

 slightly stronger below the suture, but far less so than in N. canrena. 



Alt. 23.5, diam. 24 mm. (type). 

 " 23.5, " 26.2 " (largest specimen). 



2 Trans. Wagn. Inst., Ill, p. 339, PL 20, fig. 86. Pliocene of the Caloosahatchie, 

 also recent, Watling Island, Bahamas. 



