. 
MIOCENE MOLLUSCA AND CRUSTACEA. 127 
Family TRICHOTROPID<%. 
Genus TRICHOTROPIS Broderip. 
TRICHOTROPIS DALLI n. Sp. 
Plate xXx111, figs. 1-4. 
Carinorbis (Delphinula) globulus (H.C. Lea) Heilprin, Acad. Nat. Sci. Phila., 1887, 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 apex 
slightly mamillated; 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, with flattened interspaces, the upper 
ridge being 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 7. borealis Sow., trom the Newfound- 
land coast, but differs in its shorter, broader form, being 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 Carinorbis (Delphinula) globulus 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 higher 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. Delphinula globula Lea is the same as Carinorbis 
lata Conrad. The 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. 
