372 
ACTIXOPTERVGII. 
in parts by transverse fractures. An impression of part 
of the frontal region bears traces of minute tubercles 
arranged along the radiating lines of growth. The oper- 
culum is quite smooth. The vertebral centra are delicate 
much-constricted cylinders, apparently pierced by a 
persistent thread of notochord ; and large transverse 
processes bearing the ribs are conspicuous in the anterior 
portion of the abdominal region. Long, very slender 
intermuscular bones are also seen. The neural an 
haemal spines in the caudal region arc very short, broad, 
and recumbent. The pelvic fin-supports are expanded 
laminae, and the anterior pelvic fin-spine is nearly as long 
and stout as tho foremost divided ray, which seems to be 
followed by five others. Of the dorsal fin, only a fragment 
is distinguishable opposite to the anal. The diminutive 
anal fin-spine is borno by a considerably exp a rule 
support ; while the length of the foremost divided ana 
ray probably exceeds the doptb of the trunk at its insor 
tion. The imperfect caudal fin, consisting of very broad 
rays, seems to have been forked. A series of enlarge 
dermal scutes is only preserved between the pelvic an 
dorsal fins on one side : but the whole of the trunk 
covered by very small, rounded or rhomboidal scutes o 
uniform size, which do not appear to have been m 
contact. Purchased, 1862. 
Genus AULORHYNCHUS, Gill. 
[Proc. Acad. Nat. Sci. Fhilad. 1861, p. 169.] 
Syn. Auliscops, W. Peters, Monatsb. k. prouss. Akad. 1866, P- 
Protosyngnathus, W. von der Marck, Palmontogr. vol. xxii. 18/6, 
p. 406. 
PremaxilliD much expanded, and mandible prominent ; marginal 
teeth acute, almost in one series ; palate toothless. Vertebrae about 
50 or 60 in total number, rather more than half being in the cauda 
region. Pelvic fins far forwards, with one spine and four divide^ 
rays, their supports in contact w-ith the pectoral arch. About -o 
separate spines, diminutive and equal in size, in front of dorsal tin , 
soft dorsal and anal nearly equal and opposite, acuminate in front , 
caudal fin small, slightly forked. No scales, but small bony scutes 
buried in skin in few longitudinal series. 
Only one existing species of this genus is known from the b or i 
Pacific Ocean. 
