254 
ACTINOPTEKYGII. 
Opisthopteryx gracilis^ Pictet & Humbert. 
1850. Mesogaster gracilis, F. J. Pictet, Poiss. Foss. Mt. Liban, p. 24, 
pL iii. fig. 2. 
1866. Opistopteryx gracilis, Pictet & Humbert, Nouv. Recb. Poiss. 
Foss. Mt. Liban, p. 80, pi. xi. figs. 1-4. 
1887. Opistopteryx gracilis, J. W. Davis, Trans. Hoy. Dublin Soc. [2] 
vol. iii. p. 569. 
1887. Opistopteryx curtiis, J. W. Davis, ibid. p. 569, pi. xxxii. fig. 3. 
[Fish distorted by criisbing; Edinburgli Museum.] 
Type. Distorted fish, wanting caudal fin ; Geneva Museum. 
The type species, attaining a length of about 0*1. Length of 
head with opercular apparatus equalling about twice the maximum 
depth of the trunk and contained approximately four times in the 
total length of the fish. Longest ray of pectoral fins extending to 
the origin of the pelvic fins, which are about two thirds as large 
as the pectorals and arise midway between the latter and the anal; 
dorsal fin deeper than long, with about 11 rays, its origin as far 
from the occiput as is its termination from the base of the caudal 
fin; anal fin nearly as deep as the dorsal but less extended, with 
only about 8 rays, arising midway between the pectorals and the 
caudal. 
The fossilised examples of this fish are usually much distorted, 
but its general characters and proportions seem to be correctly 
stated in the above diagnosis. One specimen, evidently shortened 
by crushing, is described by Davis under a distinct specific name, 
O. curtus. 
Form. ^ Log. Upper Cretaceous : Mt. Lebanon, Syria. 
P. 1886. Fine specimen slightly elongated by crushing, displaying 
the separate neural spines in the abdominal region; 
Sahel Alma. Egerton Coll. 
49604. Another fine specimen with head and anterior abdominal 
region distorted; Sahel Alma. Traces of the relatively 
large, pointed gill-rakers are seen. Lewis Coll, 
47357-58, 47816, 49594. Four more imperfect distorted specimens, 
with traces of the minute teeth and well-developed gill- 
rakers ; Sahel Alma. Lewis Coll. 
Genus SCOPGLOIDBS, Wettstein. 
[Fischfauna Tertiaer. Glarnerschief. 1886, p. 55.] 
Head large and trunk elongate-fusiform. Mandibular suspen- 
sorium much inclined backwards ; jaws slender; teeth moderately 
