MOLLUSCA. 729 



Trachytriton ? multivaricosum Whitfield. 

 Plate LXXXIV., Figs. 15-18. 

 1892. Trachytriton ? multivaricosum Whitf., Pal. N. J., vol. 

 2 (Monog. U. S. G. S., vol. 18), p. 61, pi. 5, figs. 

 12-13. 



Description. — "Shell of medium size and rather ventricose, 

 with an elevated spire, which is composed of rounded and ventri- 

 cose volutions, and has an apical angle of about 50° ; volutions 

 four and a half or five in the cast, the number not definitely- 

 known, the specimens being imperfect at the apex; sutures very 

 distinct and marked; body volution proportionally large and 

 full, especially in the upper part, and slightly extended below; 

 the beak rather long, slightly twisted, and provided with a rather 

 large canal; aperture large, elongate-elliptical, acute above and 

 extended below, the length about three times the width; colu- 

 mella, as shown by the cavity left by its removal, rather strong 

 and perfectly smooth; surface of the cast showing remains of 

 numerous closely arranged, vertical folds, marking the upper 

 portion of the volutions, but becoming indistinct on the outer 

 half of the last one; three of these on each volution slightly 

 stronger than the others; also, marked by spiral 'lines or ridges, 

 which have left deep grooves on the inner surface of the volu- 

 tions of the cast, and also mark the outer half of the body whorl, 

 becoming quite distinct on the margin of the lip, indicating 

 crenulations or denticulations on its inner surface." (Whitfield.) 



Remarks.- — -This species resembles T. adanticum, but it is more 

 robust with rounder volutions and usually with somewhat more 

 conspicuous and more numerous vertical nodes upon the casts. 

 The illustrations of the species published by Whitfield, show 

 the vertical nodes and the revolving costse near the aperture, 

 much more clearly than they can be seen on the specimen itself. 

 The revolving costse are so- faint as to be scarcely recognizable 

 upon the specimen at all, and upon only one of the type speci- 

 mens are the vertical nodes at all noticeable. 



Formation and locality. — Navesink marl, Crosswicks Creek, 

 near New Egypt (Whitfield). 



Geographic distribution. — New Jersey. 



