68 
PROFESSOES T. W. BRIDGE AND A. C. HADDON 
II. Historical, 
It is unnecessary for us to say anything under this head. Excellent historical 
summaries of the various views that have been held by different writers as to the 
modifications of the anterior vertebrm and the homologies of the “auditory” ossicles 
in the Ostariophysese generally, are to be found in the papers of Baudelot (1) and 
Sorensen (37). 
III. Morphology. 
In describing the morphology of the air-bladder and Weberian ossicles, and the 
nature of the modifications which the anterior vertebne undergo in the various species 
of Siluridie that we have had the opportunity of examining, we propose to follow the 
system of classification adopted by Dr. Gunther in the British Museum Catalogue of 
this family (15) and to deal with the different species under the principal subdivisions 
to which they are referred in that work, commencing however with the sub-family 
Siluridae Proteroptene. A comparison of the species enumerated in the Catalogue 
with those described in our paper will to some extent indicate the range of our 
investigations. As we have followed Dr, Gunther in the specific names, we have 
omitted the authorities for them in the text, but, in the few instances in which the 
species are not referred to in his Catalogue, the authority is given either in the text 
or in the index of species. 
Sub-Family SILURID.® PROTEROPTER.®. 
Group : — Bagrina. 
Macrones nemurus. 
We select for detailed description, in the first place, the Javan species Macrones 
nemurus. 
The Vertehixd Column . — 'In this species certain of the anterior vertebroe, from the 
second to the seventh inclusive, are rigidly connected with one another, partly by the 
anchylosis of more or fewer of their centra, neural arches, and spinous processes, and 
partly, also, through the investment of the lateral surfaces of their centra by a con- 
tinuous deposit of superficial bone. With the exception of those belonging to the 
second, third, and fourth vertebree the distinctness of the different vertebral elements 
is, however, always more or less clearly indicated by the existence of well-marked 
intervertebral spaces between the centra, which are very obvious in a vertical longi- 
tudinal section of this region of the vertebral column, and by the presence of sutures 
between certain of the confluent neural arches. The neural spines, on the other hand 
(with the exception of those belonging to the third and fourth vertebrae which are 
fused, and the spine of the second vertebra which is absent), are distinct, although, for 
the most part they arc firmly united together, but only by suture. Not only are the 
