no. 1617. NEW CRETACEOUS AND TERTIARY FOSSILS—ARNOLD. 3863 
incremental lamelle, which are most prominent on the tops of the 
ribs. Interior and details of apical hole unknown. 
Dimensions—Lenegth, 16 mm.; latitude, 10.2 mm.; altitude, 2.6 mm. 
Notes.—No intercalated riblets were noted on any of the specimens 
examined. ‘This species appears to be closest to 7. volcano Reeve of 
the recent fauna, but differs from it in being smaller, relatively more 
depressed, and having the apical hole less central and the ribs fewer, 
farther apart, and more regular and more regularly disposed over 
the surface. 
Named in honor of Dr. James Perrin Smith, professor of paleon- 
tology, Stanford University. 
Type.—Nearly perfect specimen, Cat. No. 165484, U.S.N.M. 
Horizon.—Martinez (?) formation, lower Eocene. 
Locality.—Santa Cruz quadrangle, San Mateo County, on ridge 
between headwaters of San Lorenzo River and Pescadero Creek. 
(H. 8. Gay, R. Arnold.) 
SAN LORENZO (OLIGOCENE) SPECIES. 
ECHINOIDEA. 
Genus CIDARIS Leske. 
CIDARIS BRANNERI, new species. 
Plate X XXIII, fig. 5. 
Description—Test unknown. Spines, long, slender, circular in 
cross-section, attaining a length of at least 25 mm. and a diameter of 
over 2mm. Surface of spine smooth for about one-fifth its length 
from the base; above this it is ornamented by 10 longitudinal rows of 
elongated nodes or granules which are barely connected near the 
smooth portion, but which partake more and more of the character 
of nodose ribs toward the distal end; the last one-fifth of the spine 
is ornamented by 5 prominent, slightly nodose ribs; the extreme end 
is blunt and rounded; collar at base only faintly developed. 
Dimensions.—Length, 20 mm.; diameter, basal end, 2.2 mm.; distal 
end, 1.1 mm. 7 
The spines of this species are easily distinguishable from those of 
C. merriami, new species, from the Eocene, by their smaller size, fewer 
but much more prominently nodose longitudinal ribs, and smooth 
basal portion. No complete spine of C. merriamé was obtained, so 
that the smooth basal section may possibly be a characteristic of this 
latter species as well as of (. brannert. (See note under description 
of C. merriami, p. 359, for a discussion of the zoologic relations of this 
species. ) | 
Named in honor of Dr. John Casper Branner, professor of geology, 
Stanford University. 
