190 
PROFESSORS T. W. BRIDGE AND A. C. HADDON 
away along the line of junction of the latter with the transverse process of the fifth 
vertebra in the roof of the bony funnel. As the two ridges traverse each side of the 
complex vertebra they enclose between them a well-marked groove, the anterior end 
of which coincides with the position of the external atrial aperture, while the posterior 
extremity opens into the proximal portion of the cavity of the funnel ; this groove 
lodges the anterior portion of the tripus (tr.), and, at about the middle of its extent, 
deepens into a pit on the side of the complex ceutruni for the reception of the 
articular process of the same ossicle. It may be remarked that the groove is almost 
an exact repetition of the one already described in Bagarius Yarrellii, both as 
regards its mode of formation and contents, while the ridge, which forms its ventral 
boundary, we identify in each case as the equivalent of the oblique lateral ridge of the 
complex centrum in the more normal Siluridm. 
Superficial ossifications thicken the sides, and more especially the ventro-lateral 
margins of the complex and fifth vertebral centra, and also form the lateral boundaries 
of a median aortic groove ; in addition, they invest tlie lateral and ventral surfaces of 
the body of the first vertebra and the basioccipital, including the junction of the 
former with the complex centrum, so that the first intervertebral suture, which 
is visible on the ventral surface, is the one between the complex and fifth centra 
(fig. 78). The dorsal lamina of other Siluridm is represented in Clarias by a thin and 
somewhat flexible process of bone [d.l.) which appears to become detached from the 
oblique lateral ridge of the complex centrum (?.r.)at the point where the latter passes 
on to the ventral surface of the transverse process of the fourth vertebra, and from 
thence extends obhquely downwards, inwards, and a little forwards towards, but 
without quite reaching, the lateral surface of the complex centrum, eventually 
terminating in a thickened and somewhat hook-shaped free extremity Traced 
outwards from its nodular free extremity along the roof of the funnel the dorsal lamina 
becomes confluent with the oblique lateral ridge, but may, nevertheless, be traced as a 
faint flattened projection, with a ridge-like posterior margin, extending along the 
hinder edge of the transverse process of the fourth vertebra as far as its distal 
extremity. There can be no doubt that the hook-shaped extremity of the lamina 
corresponds to the radial nodule of other Siluridse, inasmuch as it receives the inser- 
tion of the radial fibres of the tripus (fig. 81), but, instead of being firmly adherent to 
the side of the complex centrum, the nodule has become detached therefrom and 
fused with the inner or free extremity of the dorsal lamina. The anterior 
extremity of the mesonephros passes forwards between the free portion of each 
dorsal lamina and the complex centrum, across the flat roots of the modified trans- 
verse processes, and the posterior cardinal vein takes a precisely similar course on its 
way to join the Cuvierian duct of its side. Such other local developments of the 
superficial ossifications as the oblique lateral ridges of the complex centrum and 
the ventral processes hav’e been already described. 
In the arrangement of the foramina for the exit of the anterior spinal nerves from 
