A. 8. Woodward—British Jurassic Fishes. 451 
side of the jaw and exhibits the abraded remains of a series of teeth, 
of moderate size, firmly implanted in sockets; while the splenial is 
a short, stout, lenticular bone, perhaps entering somewhat into the 
symphysis, but having its thickest portion immediately behind, 
supporting two great rounded tusks, in sockets, accompanied in front 
and behind by an irregular cluster of relatively minute stout conical 
teeth. 
4. Hypsocormus tenuirostris, sp. nov. 
The second species of Hypsocormus in Mr. Leeds’ collection is 
represented by an imperfect snout, associated with a right maxilla 
and portions of splenial and dentary bones (No. 40). The original 
fish must have attained only about half the size of the typical speci- 
men of H. Leedsi; and it is readily distinguished by the narrow, 
somewhat elongated, and acutely pointed form of the snout, which, 
however, exhibits the characteristic superficial granulations. The 
pair of tusk-like teeth is placed relatively further backwards than 
in H. macrodon and H. Leedsi, and seems to have been directed 
more nearly vertically than in the latter species; so far as can be 
ascertained, a single irregular series of teeth of small size also 
occupies the margin of either side, being accompanied only by few 
minute teeth. The maxilla is very slender, externally tuberculated, 
and provided with a single series of teeth of moderate size, well- 
spaced and nearly uniform, and flanked externally by a few minute 
teeth; the anterior end of the bone terminates in a stout, smooth 
projection, slightly directed inwards. The portions of dentary bones 
are somewhat broken, but this element is stouter and larger than 
the maxilla, provided with a single spaced series of much larger 
teeth, irregular in size, the most powerful being situated in the front 
portion of the posterior half of the bone; a cluster of minute teeth 
also occupies the whole of the external margin. As in the other 
species of Hypsocormus, all the teeth are oval or round in section, 
not keeled, though more or less vertically striated ; and the enamelled 
apex often occupies less than half of the exserted portion. 
So far as can be ascertained from the foregoing specimens, there 
is a singular resemblance between the dentition of Hypsocormus and 
that of the long-snouted Protosphyrena of the Upper Cretaceous. In 
the last-named genus there are two great upper teeth at the base of 
the snout,’ while two equally large teeth occur on either side of the 
lower jaw near its anterior extremity; the latter, moreover, are 
similarly fixed in a short stout, lenticular splenial bone immediately 
behind the mandibular symphysis.’ 
It may be added that the genus Hypsocormus also occurs in the 
Kimmeridge Clay of Weymouth, portions of jaws being preserved 
in the British Museum (No. 42,368). 
5. Leedsichthys problematicus, gen. et sp. nov. 
For some years Mr. Alfred N. Leeds, of Eyebury, has obtained 
1 W. Davies, Gzor. Mac. Dec. II. Vol. V. (1878), Pl. VIII. Fig. 3. 
2 F. Dixon, ‘Geol. and Foss, Sussex’? (1850), pl. xxxi. fig. 12. 
