19 
(PI. IV, Fig. 4, op.) is nearly an isosceles triangle, of which the base-line 
measures half the height. The suboperculum (restored in PI. IV, Fig. 4, sop., 
from No. d) is as deep as the operculum and much wider, almost trapezoidal 
in shape, with the upper edge little more than half as long as the lower edge. 
The branchiostegal rays (PI. IV, Fig. 3. hr.) are rather broad plates, 
arranged in at least twelve pairs, of which the foremost is the broadest, 
evidently with the usual median plate in front. 
Vertebral Axis . — Owing to the partial absence of scales, and to the 
thinness of those that remain, traces of the vertebral axis are observable in 
all specimens. A vacant space indicates that the notochord must have been 
persistent, while the vertebral arches have the appearance of being only 
superficially calcified. These arches are stout, and the type specimen exhibits 
about twenty-four in regular close series between the occiput and the origin 
of the dorsal fin, wdiich is approximately the beginning of the caudal region. 
Each neural arch in the abdominal region consists of a deep pair of laminse, 
surmounted by a stout and scarcely shorter, separate neural spine, which is 
truncated at the upper end. Behind the origin of the dorsal fin the neural 
spine disappears, and the arch consists only of the still separate pair of 
laminse. The haemal arches in the abdominal region are merely paired 
knobs of cartilage, which are well seen in the type specimen (ha.), where the 
middle part of the series is accidentally displaced downwards. The lisemal 
arches in the caudal region are as short as the opposed neurals, to which they 
appear to he similar. One fragment of caudal fin (PI. IV, Fig. £>), which 
probably belongs to this genus and species, exhibits a row of endoskeletal 
cartilages supporting the dorsal fulcra (/.), only somewhat smaller than the 
equally well-preserved hpemal arches (ha.) supporting the rays of the 
lower lobe (c.). 
Appendicular Skeleton . — The pectoral arch is tolerably well shown 
both in the type and in other specimens, and does not appear to be 
ornamented. The supraclavicle (PI. IV, Fig, 2, scl.) is nearly as long as the 
clavicle, and meets the latter at a considerable angle. It is widest above 
and tapers somewhat below, while its outer face sometimes exhibits the oblique 
channel for the usual traverse of the lateral line. The clavicle (cl.) is 
slender, deeply overlapping the ascending process of the infraclavicle, which 
appears in the type specimen as a small triangular plate just below the 
insertion of the pectoral fin. At the upper end of the clavicle there is a 
large postolavioular plate (pci,), which is considerably deeper than broad, 
