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PROFESSORS T. W. BRIDGE AND A. C. HADDON 
outwards and confluent with the transverse process of the fourth vertebra (fig. 47). 
The oblique anterior and posterior margins of the ossifications are nearly straight, but 
the posterior is much the longer of the two. As in Platystoma, the lateral extension 
of the ossifications from the sides of the vertebral centra on to the contiguous transverse 
processes converts the cardinal grooves into complete canals, the length of which 
nearly coincides with that of the series of modified and rigidly articulated vertebrm, 
but unlike Platystoma, the ossifications are not traversed by wavy or other lines 
indicative of intervertebral sutures. 
A stout radial nodule is firmly attached to each of the lateral surfaces of 
the complex centrum near its anterior extremity, and at the base of the sub vertebral 
process (fig. 47, r.n.). A faint oblique lateral ridge traverses each of the antero- 
lateral margins of the sub vertebral process but scarcely reaches the radial nodule. 
The dorsal lamina (fig. 47, d.l.) is represented by a thin slender process of bone, 
which is prolonged from the radial nodule obliquely backwards and upwards, ventrad 
to the posterior cardinal vein, and finally blends with the ventral surface of the 
transverse process of the fourth vertebra. The posterior margin of the lamina 
is suturally joined, to the anterior margin of the superficial ossification of the 
same side, and, consequently, to a slight extent, lengthens the corresponding 
cardinal canal. 
The presence of transverse processes in connection with the centrum of the first 
vertebra is very exceptional in the Siluridse. IIamsay Wright (42), however, has 
described a pair of very rudimentary processes in Amiurus catus, and a pair of short 
spicular outgrowths from the first vertebra in Arius pidada may possibly have a like 
significance, but that they correspond to those carried by the succeeding vertebrae is, 
to say the least, very doubtful. The transverse processes of the fourth vertebra are 
greatly developed. Each is somewhat fan-shaped, with a flattened and contracted 
root, and an expanded distal portion (figs. 45 and 47, tp^). The anterior portion, 
representing the anterior division of the process {t.pAa.), is slightly thickened and 
strongly decurved, and, moreover, is produced distally into a pointed process which 
is applied to the cleft stem of the post-temporal so as to form, completely or partially, 
the posterior boundary of the socket for the clavicle. The posterior portion of the 
transverse process, which is much thickened, inclines obliquely backwards as well as 
outwards, and represents the usual posterior division of the process {t.p^p.). An 
extremely thin, curved, and apparently somewhat flexible lamina of bone extends 
between and connects the thickened anterior and posterior divisions. The relative 
thinness of this lamina, combined with the existence of a deep notch between the 
decurved anterior division and the complex centrum for the reception of the posterior 
section of the tripus, renders the anterior division slightly flexible and apparently 
capable of a limited amount of motion in an upward and forward direction. The 
transverse process of the fifth vertebra {t.p.^) is much smaller but longer and more 
expanded than any that follow. Its distal extremity is free, but for the greater part 
