PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 1617 
ARTICULATA. 
VERMES. 
Genus SPIRORBIS Lamarck. 
SPIRORBIS? DICKHAUTI (sp. noy.). 
Shell discoid, one side being nearly flat and the other broadly um- 
bilicate; volutions about five, partially embracing but all of them visible, 
somewhat rugose but increasing in size with considerable regularity ; 
peripheral side of the volutions flattened or gently convex, having a 
single revolving raised line along its middle and another similar one 
at each border, where it sharpens the angularity between the: latera] 
and peripheral sides; outer portion of both the lateral sides of the 
volutions concave, and the inner portion convex, giving the last-named 
portion a greater transverse diameter than the outer portion, the larger 
part of which is embraced by the next succeeding volution; aperture 
small, round, and apparently, but not really, contracted. The cavity 
being round, the outer portion of the test only partakes of the irregu- 
larity described, and seems to have been deposited as an encrustation | 
upon the first-formed inner portion, that of adjacent volutions seeming — 
to blend, obscuring the suture. Besides a considerable degree of rugosity, 
the surface shows under the lens a peculiar granular or rather an 
etched appearance. 
Greatest diameter of the full coil of the largest example discovered, 
9 millimeters; greatest diameter of the outer volution, near the aper- 
ture, 24 millimeters. (Museum No. 9073.) 
In size and general aspect this species resembles S. votulus Morton 
sp., from the Cretaceous of New Jersey, but although doubtless con- 
generic, it differs from that species in the character of its surface orna- 
mentation, and in having a round instead of quadrangular aperture. 
This shell is referred to the shell-bearing worms and not to the mollusca 
on account of the peculiar character of the test. It probably does not 
strictly belong to the genus Spirorbis, but it is regarded as at least a 
closely related form. 
Position and locality.—Cretaceous strata near Little Rock, Ark., 
where it was obtained by Mr. E. O. Ulrich, and also by Mr. H. E. 
Dickhaut, in whose honor the specific name is given. 
CRUSTACEA. 
Genus CALLIANASSA Leach. 
CALLIANASSA ULRICHI (sp. nov.). 
Hand quadrate, flattened; inner face less convex than the outer; both 
upper and lower edges acute, the lower one more so than the upper, and. 
finely crenulate; fixed finger slender, plain, its transverse section sub- 
Proc. Nat. Mus. 80 11 Aug. 24, 18890. 
