1921] NATURAL SCIENCES OF PHILADELPHIA. 339 



thsLii in L. puIcheU a; the anterior spirals are stronger; finally the 

 apical whorls differ. In L. pulchclla there are 1^ smooth whorls, 

 the first one globose and bulging, the second narrower. In L. soror 

 the summit is smaller, the whorls increasing regularly, and there 

 are If smooth ones. These differences certainly indicate specific 

 divergence. 



Aurinia striata (Gabb) Plate XXIII, flg. 9. 



Scapha striata Gabb, Tr. Am. Philos. Soc, xv, 1873, p. 219. 



Scaphclla {Aurinia) striata Gabb, Dall, Trans. Wagn. Inst, iii, 1890, p. 88. 



The rounded summit (f of a whorl) is worn; after that all of the 

 whorls are closely striate spirally. The first 2f whorls have a sub- 

 cjdindric shape; then small nodules appear above the middle, which 

 becomes subangular. The last whorl has a prominent rounded ridge 

 at the shoulder, closely set with about 22 compressed nodes. Two 

 columellar plaits remain on the type, which is broken anteriorly. 

 In a very young one there are three. 



Length as broken 25, diam. 11.5 mm. Nearly 5 whorls. 



Gabb's type, no. 3274 A. N. S. P., is a young shell; another 

 13 mm. long was taken. The consideration of the species by Dall 

 referred to above, should be consulted. 



MITRIDAE. 



Mitra henekeni Sowerby. 



Mitra henikeri Sowerby, Q. J. Geol. Soc, vi, p. 46, 1849, pi. 9, fig. 5. 



Adult specimens have but two columellar plaits, with sometimes 

 the very weak trace of a third; in young specimens the third plait 

 is more distinct. Sowerby 's illustration is good, though the speci- 

 men was incomplete. 



M. henekeni resembles the following species, but it is less slender, 

 the whorls are more convex, and are acutely carinate below the chan- 

 nelled suture. 



Length 58, diam. 15 mm. Broken specimens indicate that it 

 reaches a length of about 65 mm. 



Mitra longa Gabb. Plate XXIV, flg. 3. 



Mitra longa Gabb, Tr. Am. Philos. Soc. xv, 1873, p. 219. Brown and Pilsbry, 

 Proc. A. N. S. Phila. 1911, p. 346, pi. 24, fig. 11. 



A very slender shell with three well-developed columellar plaits 

 and traces of two more. The acute spiral cords alternate with 

 smaller ones, the intervals having some spiral threads, more num- 

 erous near the base. The intervals are crossed by even, fine axial 

 threads. 



