CHONDROSTEIDiE. 
35 
Type. Various bones ; British Museum. 
The type species, of large size, probably attaining a length of not 
less than six or seven metres. Most of the external head-bones 
apparently ornamented with large, well-spaced tubercles, those on 
the suboperculum (?) tending to an arrangement in radiating lines. 
Maxilla smooth, its length somewhat more than twice as great as 
its maximum depth at the anterior expansion ; the supposed sub¬ 
operculum as broad as deep, with excavated anterior border. 
Caudal fulcral scales smooth, or only in part faintly rugose. 
Form. Sf Log. Upper Lias : Yorkshire. 
The following specimens were all obtained from the cliffs in the 
neighbourhood of Whitby. 
36185. A large slab displaying numerous bones, among which may 
be recognized the hyomandibular, ceratohyal, supposed 
suboperculum, clavicle, supraclavicle, fragments of squa¬ 
mous tuberculated bone, and portions of fin-rays. The 
bone interpreted as suboperculum closely resembles that 
element in Chonclrosteus , but is not coated with ganoine, 
being covered with coarse tuberculations, of which a few 
are arranged along the radiating lines of growth. 
Purchased , 1861. 
P. 3356 d-f. Three small slabs exhibiting various bones in a more 
or less fragmentary state. The left clavicle, probably 
belonging to the first slab, is shown from the outer aspect, 
of one-sixth the natural size, in fig. 14 (p. 40), and is 
described and figured by the present writer in Proc. Geol. 
Assoc, vol. xi. pp. 34, 35, fig. 4. The second slab in¬ 
cludes part of a spatulate bone, with remains of an 
external tubercular ornament. The third slab exhibits 
the bones in a remarkably friable and crushed condition, 
partly pyritised, and comprises both supraclavicles, some 
fin-rays, and part of a hyomandibular. 
Enniskillen Coll. 
P. 2362 a, b. Two examples of the parasphenoid bone, the first most 
nearly complete and shown of one-quarter the natural 
size, from the inferior aspect, in fig. 7. The general form 
of the element is much like that of the modern Acipenser 
(fig. 8), but the expansion at the origin of the basiptery- 
goid processes is wider. Egerton Coll. 
d 2 
