ON THE ANATOMY OF FISHES. 
103 
the succeeding transverse process. The anterior division is unusually stout, 
with a broad flat root, which is in relation by its ventral surface with the tripus, but 
flattened from before backwards for the remainder of its length. It has but a slight 
downward curvature, and, instead of being prolonged into a crescentic distal portion, 
as in Maciones, has its thick truncated extremity firmly applied to the inner moiety of 
the cleft post-temporal stem in such a way as to deepen the articular groove for the 
clavicle by strengthening its inner margin, and at the same time entirely excludes the 
post-temporal from contact with any portion of the anterior wall of the air-bladder. 
From this arrangement it will follow that the transverse processes alone furnish the 
usual bony buttresses for the antero-lateral regions of the bladder, in addition to 
aflbrding a firm and rigid support to the pectoral girdle. At their junction the post- 
temporal and transverse process are firmly united together by ligament. A transverse 
membrame stretches between the distal extremities of the anterior divisions of the 
modified transverse processes, in close relation with the proper anterior wall of the 
bladder, and elsewhere has the same skeletal attachments as in Macrones. 
The air-bladder has fairly thick walls, and is subdivided in the usual way into an 
anterior and two lateral compartments. Relatively to the anterior chamber, the lateral 
compartments are somewhat larger than is usually the case, and extend backwards in 
the abdominal cavity as far as the origin of the seventh pair of ribs. The primary 
transverse septum is exceptionally narrow, and forms a stout column of vertically 
disposed fibres. The longitudinal septum is incomplete posteriorly, so that the two 
lateral chambers communicate with each other directly, as well as indirectly, through 
the anterior compartment. There are no secondary transverse septa, and both the 
anterior and lateral compartments have smooth non-sacculated walls. In all other- 
points the air-bladder closely resembles that of Macrones nemurus. 
The outer surface of each lateral cutaneous area is rendered very conspicuous by a 
large circular patch of black pigment, surrounded by a white margin. 
The Weberian ossicles are also very similar to those of Macrones; the tripus, 
however, has no heel-like process. The relative lengths of the anterior and crescentic 
processes of this ossicle are 8 mm. and 6 mm. respectively, instead of being approxi- 
mately equal. 
The posterior wall of the atria sinus imparis is strengthened by a spicular uj)growth 
from the dorsal margin of the hinder face of the basioccipital, as in Macrones aor. 
Pseudohagrus fulvi-draco. 
The skeleton, air-bladder and Weberian ossicles of this species are precisely similar 
to those of P. hrachysoma. 
Liocassis micro'pogon. 
In this and the next species {Bagroides melanopterus) we meet with a reversion to 
the Macrones type. 
