NERINEA (CRYPTOPLOCUS) LIBANENSIS. 27 



Shell turbinate-conical, longer than broad, widely umbilicated ; angle of 

 spire 32° : whorls about seven or eight, flattened, transversely suleate, 

 banded above at the suture, the last angled below: aperture subquadrate. 

 The other characteristic marks are unknown by reason of imperfection of 

 the specimen. 



Single specimen, a fragment retaining the test. Length, 37 mm. ; when 

 entire, about 50 mm. ; width, 28 mm. 



In respect to size, general proportions, and the sutural band, (his shell is 

 very similar to Cryptoplocus cingulaius Zittel, 1S73 (Gastrop. der Stramb. 

 Schichten, p. 2G1, PI. xlii, fig. 20). which, however, from the basal angle 

 upwards is girt with granular ridges. In this specimen, although the test 

 is so much decayed that the original character of its surface is obscured, 

 it can be seen that each whorl was marked with a few distant encircling 

 furrows, but the nature of the intervening ridges is uncertain. The last 

 volution, near the mouth, has been thrust inward enough to compress the 

 aperture somewhat, and to encroach upon the umbilicus, which originally 

 must have been wide and circular. The aperture shows the absence from 

 the labrum and columella of the folds which characterize Nerinea proper, but 

 is so closed by stony deposit that it is impossible to determine whether the 

 single concealed fold upon the hinder part of the inner lip, peculiar to 

 Cryptoplocus, is present or wanting. Yet the wide and round umbilicus, the 

 quadrate mouth without canal, and their relations to each other, sufficiently 

 distinguish this species from Turritella, Certthimn, and Trochus, the only genera 

 with which it could be confounded. 



The resemblance of this fossil to several varieties of Nerinea pyramidalis 

 Minister, to X. depressa Voltz (iV. umbilieata Voltz) and Trochus monoplicus 

 d'Orb., all of which are now recognized as species of Cryptoplocus, tend to 

 support our view of its generic relations. 



Pictet and Campiche classified Cryptoplocus as a genus distinct from 

 Nerinea, while Zittel (Gastrop. der Strand). Schichten, p. 2o7, 1873, and 

 Ilandb. der Palseont., I. Band, 2. Abtheilung. p. 247, 1882) regards it as a 

 subgenus of Nerinea. Coll. .Merrill. 



Locality and Position, — Beirut district; from an arenaceous marl, prob- 

 ably Turonian. 



