MIOCEXE MOLLUSCA AND CRUSTACEA. 127 



Family THICHOTROPID.E. 



Genus TRICHOTROPIS Brodeiip. 



TRICUOTKOPIS DALLI 11. sp. 



Plate, xxiu, tigs. 1-4. 



Carinorbis {Delphiniila) (jlobulm (H. C. Lea) Heilpriii, Acad. Nat. Sci. Phila., 1SS7, p. 

 404. 



Shell rather small, obliquely ovate, ventricose; body volution forming 

 nearly the entire bulk, very ventricose on the side and below, and some- 

 what flattened on the shoulder. Volutions about four in number, the ajjex 

 slightly maraillated; aperture round-oval, nearly as wide as long, the peri- 

 stome entire, in contact with the preceding volution on the upper inner side, 

 but not coalescent; umbilicus small but distinctly open. Surface marked 

 by six strong, elevated, spiral ridges, Avith flattened interspaces, the \\\^\wv 

 ridge i)tnng a little the strongest. These spiral ridges often appear double 

 on the surface, from the effect of weathering, but when perfect they are 

 rounded. There are also finer but distinct transverse raised lines, which 

 cross the spiral ridges, and are distinct on the interspaces, but faint or even 

 obsolete on the spiral ridges. Inner margin of the lip faintly marked by 

 depressions corresponding to the spiral lines. 



This species somewhat resembles T. boiealis Sow., from the Newfound- 

 land coast, but differs in its shoi-ter, broader form, Ijeing only about two- 

 thirds as high proportionally; also in the much stronger spiral ridges. Prof 

 Heilprin has sent me, for examination, the specimen which he had identified 

 as CarimrUs {DelpMnula) ylohalus H. C. Lea, from the collection of Miss 

 Tyndall, of Philadelphia. I find it to be a young shell, about an eighth of 

 an inch long, of this species. The spire is very much liigher than is repre- 

 sented in Mr. Lea's figure, which represents a shell nearly twice as wide as 

 high, while this young shell is nearly twice as high as wide, with the 

 columella nearly under the apex, instead of at the edge of the penultimate 

 whorl, as in Lea's figure. Delphrnula r/lobula Lea is the same as Carinorbis 

 lata Conrnd. Tlie present species might be referred to Isapis. 



Formation and localities : In the Miocene marls at Shiloh and at Jericho, 

 N. J. In the collection of the National Museum. 



