MOLLUSCA. 525 



Super-family ENSIPHONACEA. 

 Family CLAVAGELLIDAE. 



Genus CLAVAGELLA Lamark. 



Clavagella armata Morton. 

 Plate LVIIt, Figs. 1-2. 



1834. Clavagella armata Mort., Synop. Org. Rem. Cret. Gr. 



U. S., p. 69, pi. 9, fig. ii. 

 1 86 1. Clavagella armata Gabb, Proc. Acad. Nat. Sci. Phil. 



(1861), p. 364. 

 1861. Clavagella armata Gabb, Synop. Moll. Cret. Form., p. 



165 (109). 

 1864. Clavigella armata Meek, Check List Inv. Foss. N. A., 



Cret. and Jur., p. 15. 

 1886. Clavagella armata Whitf., Pal. N. J., vol. i (Monog. 



U. S. G. S., vol. 9), p. 192, pi. 25, fig. 24. 



Description. The dimensions of a complete internal cast of 

 the shell, exclusive of the tube, are: length, 14 mm.; height, 8.5 

 mm.; thickness, 7.5 mm. Shell subovate in outline; the beaks 

 small, situated a little in front of the middle, slightly recurved. 

 Anterior and posterior margins rather sharply rounded; ventral 

 margin convex throughout. The anterior margin with several 

 tubular spines. Valves rather strongly convex, the right one 

 free, the left one attached to the tube. Surface of the cast 

 smooth, the muscular impressions more or less strongly marked, 

 sometimes scarcely distinguishable. 



Remarks. Specimens of this peculiar species are rare in the. 

 New Jersey collections, and have been recognized only in the 

 Navesink marl. The peculiar tubular spines which arm the 

 anterior margin of the shell have sometimes been broken from 

 the fossil specimens as is the case with the specimen illustrated 

 by Whitfield. One specimen has .been observed, however, upon 

 which they are as clearly shown as upon the type specimen illus- 

 trated by Morton. The tube, except its very basal portion, is 

 rarely preserved. 



