260 ' PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. XXXIV. 
Ine as they pass from the umbilicus to the abdomen, the greater 
axes of the lateral nodes being parallel! with the coste, while the 
greater axes of the abdominal nodes are at right angles to the coste; 
coste about as strong in proportion to size of whorl on the smallest 
whorl found exposed as on the largest whorls and the nodes develop 
at an early stage; septa can not be figured from the specimens at 
hand; diameter of the type specimen 80 mm., outer whorl 31 mm. 
high and 14 mm. wide between the nodes, some fragments being 
larger than this. 
The type now in the U. 8S. National Museum (Cat. No. 30877) and 
quite a number of more fragmentary specimens in the University of 
Colorado were found by Prof. D. W. Spangler, of Longmont, Colo- 
rado, and the writer, 10 miles north of Boulder in one of the lme- 
stone bands of the upper Fort Benton shales, associated with 
Inoceramus labiatus and other Benton species. 
VOLUTODERMA ? CLATWORTHYI, new species. 
Pence SMIOOC, tikes, Als DB 
Shell of medium size, spindle-shaped; spire elevated, less than 
aperture in length above the complete last whorl; whorls about seven, 
convex, the inner casts of the upper ones roundly so, the lower 
ones somewhat flattened above and below the peripheral nodes; su- 
ture distinct but not deep in the shell, though very deep in the in- 
ternal cast; last whorl and next one above it have a broad, shallow 
sulcus just below the suture, due in part to the prominence of the 
row of nodes below, but not entirely so, as shown by the general 
flattening of that part of the inner cast; surface rough, ornamented 
by thirty or more strong, rounded, nearly equal revolving ribs, 
crossed by about fourteen strong, rather irregular, doubly-curved ver- 
tical costee, which develop into elongated nodes as they pass over the 
periphery, revolving and vertical coste both becoming nearly obso- 
lete above the nodes on the type-specimen and a smaller one, but on 
«a fragment of a larger specimen which probably belongs to this 
species there are weaker and more crowded revolving ribs above the 
nodes and a tendency toward the intercalation of additional ribs 
below the nodes; inner casts of the three lower whorls have pro- 
tuberances corresponding to the nodes, but none corresponding to the 
revolving ribs; aperture elongated, widest above the middle; length 
of type specimen about 65 mm., greatest breadth 27 mm. In general 
form (which, however, is variable in the genus), the cancellated 
sculpture of intersecting costae developing into nodes at their inter- 
sections, the unglazed surface, the rather thick shell, conspicuous 
lines of growth and nearly straight pillar, this species shows its close 
relationship to the genus fostellites Conrad as defined by Doctor 
