SCOPEJ.ID.U. 
243 
Dermatoptychus macrophthalnius , W. von dor Marck, Palasontogr. 
vol. xv. (1868), p. 287, pi. xliii. fig. 4. — Upper Cretaceous; 
Sendenhorst, Westphalia. [Impression of fish, in counter- 
part ; Academy of Munster. Type species of so-called 
Dermatoptyclms.'] 
Genus ACROGNATHUS, Agassiz. 
[Poiss. Foss. vol. v. pt. ii. 1844, p. 108.] 
Head with remarkably large orbits and narrow interorbital 
region. Mandibular suspensorium nearly vertical ; maxilla ex- 
panded behind ; teeth very minute and clustered. Vertebras 
between 30 and 40 in number. Pectoral fins delicate, inserted 
! ‘bove the ventral border ; pelvic fins comparatively large, with 7 
or 8 very stout rays, inserted far forwards ; dorsal fin short-based, 
m the anterior half of the back, without any excessively elongated 
ra y ; anal fin very small and remote ; caudal fin forked. Scales 
' ar ge, thick, and uniform, not serrated on the hinder border ; 
lateral line conspicuous. 
Acrognathus boops, Agassiz. 
1844. Acrognathus hoops, L. Agassiz, Poiss. Foss. vol. v. pt. ii. p. 108, 
pi. lx a. figs. 1-4. 
1888. Acrognathus boops, A. S. Woodward, Proc. Geol. Assoc, vo . x. 
p. 323." 
type. Imperfect distorted fish ; British Museum. 
’The type species, imperfectly known, attaining a length of about 
<)- 12. Length of head with opercular apparatus considerably 
exceeding the maximum depth, probably equalling about halt the 
le ngth of the trunk from the pectoral arch to the base of the caudal 
Dentary and angular bones of mandible marked ^ith shai]> 
radiating grooves. Seales quite smooth. 
Form. 4' Loc. Senonian : Sussex and Surrey. 
4304. Type specimen, which has lost the extremity of the tail 
sinco it was described and figured by Agassiz ; Chalk, 
Lewes. The remarkable stoutness of the pelvic fins 
compared with the pectorals is well shown. 
Mantell Coll. 
49775. Portion of mandible and anterior vertebrae; Upper Chalk. 
Shalford, near Guildford. Caprm Co11 
b2 
