170 
ACTINOPTERrGII. 
49542, 
numerous delicate intermuscular bones, so that the non- 
appearance of the characteristic short transverse processes 
is perhaps to be explained by the im perfections in the 
mode of preservation. The neural arches and spines are 
very slender, and inclined sharply backwards throughout 
the longth of trunk preserved ; the delicate ribs seem t° 
have completely encircled the abdominal cavity. Traces 
of the contents of the intestine are observed throughout 
the greater part of the abdominal region, extending behind 
the pelvic fins nearly as far as the specimen is preserved. 
One pectoral fin is bent upwards and the other down 
wards, and they are sufficiently well exhibited to indicate 
that they are comparatively large and robust, each wi 
about 10 rays. The pelvic fins ( plv .) are very remote, 
and observed to he supported by a pair of slender bone 3 
which are pointed in front. The pelvic fin-rays are mm 
more slender than those of tho pectoral fins, and perhaps 
about two thirds as long as the latter. The fish is broken 
away shortly behind the pelvic fins, and neither side o 
the fossil exhibits the additional fragment represented b) 
Davis. Still further back on the left-hand slab, there 
occurs the terminal portion of a tail with a small differ 
entiated caudal fin ; but it is very uncertain whether this 
belongs to the fish now described. The dorsal fin-supp° r ^ s 
are well shown as indicated in the drawing, each with a 
small triangular expansion at its distal end ; but there 
are no traces of fin-rays in connection with them. There 
arc no undoubted remains of scales. Lewi* v 
P. 9169. Imperfect head and greater part of abdonun® 
region, exhibiting a small fish swallowed tail foremost) r® 
counterpart. The front half of the right side of the f° ssl 
is shown of the natural size in PI. XV. fig. -• 
cranium in side-view appears less deepened than iu 
existing Notacanthug, but it has the same delicate pur® 
sphenoid bone. Tho maxilla, shown on the left 31 
of the fossil, is gently curved and comparatively sfoU ’ 
hut its hinder ond is obscured. The mandible is 8 J 
stouter, its articulation below the middle of the oibit. 
its hinder half very much deepened, its short oral marg iu 
still bearing three slender recurved teeth. The opercular 
apparatus is imperfect and distorted, but below it there 
are distinct remains of about ten delicate branchiostega 
rajs. The constricted veitebral centra are fracture®’ 
