CHOXDROSTEIDJE. 
33 
right side. The right clavicle and infraclavicle are shown, 
of the natural size, in PL I. fig. 5. The clavicle ( cl .) is 
precisely similar to that of Acipenser (fig. 15, p. 40) in 
shape, but the infraclavicle ( i.cl .) is relatively smaller than 
the corresponding element of the recent genus. 
Enniskillen Coll . 
35056. Trunk about 0*51 in length, wanting the pelvic fins. The 
anal fin is displaced, but exhibits both the series of basal 
cartilages. Purchased, 1860. 
P. 3371 a. Caudal region of a medium-sized fish, with the median 
fins somewhat crushed and broken and remains of the 
pelvic pair. Some of the neural spines of the axial 
skeleton are exhibited beneath the supports of the dorsal 
fin: and each seen in front view shows a bifurcation of 
its lower extremity. There are no distinct traces of 
haemal arches except at the base of the caudal fin. 
Enniskillen Coll. 
P. 3365. Very small imperfect caudal region, showing the pelvic, 
anal, and caudal fins. Enniskillen Coll. 
P. 3365 a. Dorsal and pelvic fins of a small fish. Enniskillen Coll. 
P. 7397. Caudal fin of moderate size. Purchased. 
P. 3365 b. Another specimen, wanting the extremity of the upper 
caudal lobe. Enniskillen Coll. 
39495. Caudal fin 0-28 in depth, displaying the caudal fulcra! 
scales, one figured in Proc. Geol. Assoc, vol. xi. pi. i. fig. 7. 
Purchased , 1865. 
P. 3368. Two examples of the caudal fin, slightly smaller. 
Enniskillen Coll. 
Chondrosteus pachyurus, Egerton. 
1858. Chondrosteus pachyurus , Sir P. Egerton, Phil. Trans, p. 883. 
V- - 
Type. Tail; Museum of Practical Geology, London. 
The undermentioned specimens indicate a fish about twice as 
large as the ordinary C. acipenseroides, which is regarded by 
Egerton as specifically distinct from the latter. So far as known, 
the cranial roof-bones are ornamented with closely-arranged fine 
tuberculations; and the caudal fulcral scales appear to be rela¬ 
tively broader than those of the type species, though also acuminate. 
Form. Sf Loc. Lower Lias: Dorsetshire. 
part hi. d 
