38 WOODWARD : FOSSIL FISHES OF THE UPPER LIAS OF WHITBY. 
the pelvic fins, the other immediately in advance probably of the 
origin of the anal fin. Each of these scales is elongate- oval in 
form, narrower behind than in front, equalling two ordinary scales 
in length, and externally ornamented with longitudinal ridges, which 
converge a little at either end. 
A second specimen shown of the natural size in pi. v. fig. 1, is of 
more importance for determining the specific characters of the fish, 
not being distorted ; but this example unfortunately wants the dorsal 
part of the caudal region. The length of the head with opercular 
apparatus is shown to be approximately equal to the maximum depth 
of the abdominal region, and would occupy somewhat less than one 
quarter of the total length of the fish. The cranium is partly 
crushed downwards, and exposed from above ; but its lateral margin 
is apparently entire, and the large excavation for the orbit (orb.) is 
conspicuous. The cheek-plates are removed, thus exposing some 
obscure remains of the pterygo-quadrate arcade ; but the maxilla 
{mx.) is nearly complete, deepest behind, and marked with coarse 
rugse which are mainly longitudinal. The mandible {md.) is imper- 
fect, ornamented with two or three longitudinal rugse near its inferior 
border, and with upwardly turned rugse above. The operculum {op.) 
wants a little of its outer surface below, and is fractured by a vertical 
crack behind ; but its maximum depth is evidently a little greater 
than its width, and the ornamented ridges on its outer face are mostly 
short, with a distinct trend postero-inferiorly. The other opercular 
plates and the branchiostegal rays are too imperfect for description ; 
while the characters of the clavicle {cl.) immediately behind are also 
obscure. The pectoral fin (^^c^.) exhibits remains of not less than 
fourteen stout rays more or less subdivided distally ; and one of the 
pelvic fins {ph. ), with at least ten rays which are distantly articulated 
in the terminal half, arises very slightly nearer to the pectorals than 
to the caudal fin. The anal fin is wanting, and there are only insig- 
nificant fragments of the dorsal {d.) and caudal (r.), the former well 
in advance of the pelvic pair. The fin-rays of the lower caudal lobe 
are distantly articulated almost from the base, and very finely 
divided distally. The scales are scarcely disturbed except where the 
fish is imperfect, and all are much broader than deep. The extent 
