70 
ACTINOPTEKTGII. 
f Hg 
margin of the jaws, larger in the mandible than on 
maxilla. The characteristic operculum, preoperculu®’ 
and enlarged lower cheek-plates, with a few of 
branchiostegal rays, are also distinct in impression. 
Enniskillen Colt- 
P. 3888. Small fish; Sendenhorst. Enniskillen Coll 
P. 2108, P. 2108 a. Three more imperfect small specimens , 
denhorst. Egerton ko 
P. 2105. Remains of small fish displaying some of the stout con ' , , 
teeth clustered on one of the inner bones of the mou ’ 
Sendenhorst. Some of the scales are also well preservo 
Egerton Coll- 
35012. Scattered remains of head and abdominal region ; ^eiidc 
horst. Appearances are not quite conclusive, hut sugr 
that the parasphenoid is a slender toothless bone, w ^ 
the inner clustered dentition is borne by the long a _^ 
laminar entopterygoid. The latter element, whatever^ 
nature may be, is only imperfectly preserved, but 
hollow bases of the teeth are shown in a patch extent 
along its middle region, not reaching the borders. , 
Purchased, 1 ®° ' 
20586. Imperfect trunk displaying parts of the fins and sow® 
of the vertebra; in section ; Stromberg. Purchased , 1 
The following specimens differ from I. grandis in the comp arat '^ 
slenderness of the trunk, and are thus of the form described u 11 
the name of Istieus gracilis (L. Agassiz, Poiss. Foss. vol. v. 1-'^' ^ 
pt. i. p. 13, pt. ii. p. 94, pi. xv. ; F. A. Roemer, Verstein. ^ 
deut-sch. Kreidegeb. 1840, p. Ill ; W. von der March, Palasontog • 
vol. xi. 1863, p. 40, pi. v. fig. 2). The type specimen, bovre^ 
in the Palaeontological Museum, Munich, and all others ot _ 
same form, seem to owe their slender proportions to distiu 
during fossilisation. 
P. 3889. Two specimens about 0-3 in length associated ° n ° ^ 
slab ; Sendenhorst. Enniskillen 
Istieus macrocephalus, Agassiz. . 
1842-44. Istieus macrocephalus, L. Agassiz, Poiss. Foss. vol. v. P 
P- 13, pt. ii. p. 93 , pi. xvi. upper fig. (non lower fig.)- 
Type. Imperfect fish ; British Museum. 
