214 
PROFESSORS T. W. BRIDGE AND A. C. HADDON 
organ need be given. Both the trIpus and scaphiinn are normal, but the iiiter- 
calariura has no horizontal process and is represented by a small bony nodule in the 
interossicular ligament. 
Pseudeutrojnus. 
We have not been able to examine any examples of this genus, which apparently 
only differs from Schilbichthys in the presence of a small adipose dorsal fin, but Day 
(9, p. 709) briefly refers to the air-bladder of three species, viz., P. atherinoides, 
P. murius, and P. goongwaree. In the first-mentioned of these species the air-bladder is 
said to be of “ large size, as wide as the abdominal cavity, and on removing its front 
wall a longitudinal septum is seen dividing it into lateral portions which, however, 
communicate anteriorly.” The same writer remarks that in some of the larger 
species, such as P. murius { = Eutro 2 )ius (?) wwrms), and P. goongivaree, “ the air-vessel 
is larger than in P. garua (= Schilbichthys garua), and comparatively considerably 
smaller than in P. atherinoides." He also adds that “ P. garua has the smallest air- 
vessel amongst the larger species which I have examined.” Day’s descriptions are 
too brief to admit of any inferences being drawn from them, except, perhaps, that the 
air-bladder of Pseudeutropius is of the normal type and exhibits considerable variation 
in size in different species. 
Pangasius Buchanani. 
In this Siluroid we meet with several interesting features, and notably the re- 
appearance of an “ elastic-spring ” apparatus, the existence of which in the East 
Indian genus Pangasius has not hitherto been recorded. Johannes Muller (28), in 
his list of those Siluridse in which he had discovered this mechanism, not only 
excluded Pangasius, but, by implication, if not explicitly, denied its existence in this 
genus. Taylor (38) and Day (9) have described the air-bladder of P. Buchanani, 
but they also failed to recognise the presence of the mechanism. 
The body of the first vertebra is fairly well developed, being visible in the floor of 
the neural canal, and also on the ventral surface between the complex centrum and 
the basioccipital (see P. djarnbal, fig. 90, v.^). The complex and two following 
vertebrjB are rigidly connected together, partly by the superficial ossifications, and 
partly by the firm sutural union and partial anch}dosis of their respective neural 
arches and spinous jwocesses. The complex centrum is very large, exceeding in 
length the centra of the fifth and sixth vertebrae taken together (c.c., v.°, u®). The 
spines of the third and fourth vertebrae are united at their bases by a thin ridge of 
bone, but are otherwise distinct, the former inclining forwards to its connection with 
the supraoccipital and exoccipitals through the intervention of a considerable amount 
of intercalated cartilage, while the latter is directed obliquely backwards, overlapping, 
and to some extent suppressing, the partially confluent spines of the fifth and sixth 
vertebrae. The seventh vertebra is quite distinct. 
