408 
actinopterygii. 
not pressed closely together ; anal fin with four large spines gradu- 
ally increasing in length backwards. Scales ctenoid, remarkably 
delicate, none enlarged or thickened. 
Homonotus dorsalis, Dixon. 
1 850. Ilomonotus dorsalis, F. Dixon, Geol. Sussex, p. 372, pi. xxxv. 
fig. 2. 
1888. Ilomonotus dorsalis, A. S. Woodward, Proc. Geol. Assoc, vol. x. 
p. 329. 
Type. Imperfect fish ; Brighton Museum. 
The typo species, probably attaining a length of about O’ 15. 
Length of head with opercular apparatus less than the maximum 
depth of tho trunk and exceeding half its length from the pectoral 
arch to tho base of the caudal fin. Dorsal margin much arched, 
the dorsal fin arising at the highest point, nearly midway between 
the tip of tho snout and the base of the caudal fin. The 12 
dorsal fin-spines feebly furrowed, and the length of some at least 
equalling half the depth of the trunk at their insertion ; the hinder 
part of tho dorsal fin comprising probably 10 articulated and divided 
rays. Anal fin with smaller and stouter smooth spines than the 
dorsal, arising opposite the hinder end of the spinous portion of the 
latter. Serrations of scales small and inconspicuous. 
Form. S( Loe. Scnonian : S.E. England. 
43264. Imperfect fish, in counterpart, with tho head-bones and 
squamation much fractured ; Upper Chalk, Bromley, 
Kent. Purchased, 1871 
33230. Remains of fish about 0-14 in length ; Upper Chalk, North- 
fleet, Kent. Purchased, 1854. 
P. 1952 a. Remains of head and trunk about 0-11 in length ; Kent. 
Eijerton Coll. 
P. 7651. Fragmentary trunk, with pelvic fin showing 6 or 7 rays 
in addition to the spine ; English Chalk. 
Purchased, 1895. 
P. 9443. Remains of small trunk, with spines of the dorsal and 
anal fins ; English Chalk. History unknown. 
39074. Fragmentary remains, showing some caudal vertebrae and 
portions of the pelvic, dorsal, and anal fins ; Upper Chalk, 
Gravesend. Bowerbank Coll. 
P. 5682. Imperfect small trunk, in counterpart ; (?) Grays, Essex. 
Harford Coll. 
