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PROFESSORS T. W . BRIDGE AND A. C. HADDON 
Amblyceps (sp. ?). 
The only reference to the air-bladder of this genus that we have been able to 
discover is by Day (9), who includes Amhlyceps in his list of Indian Siluridse in 
which the organ is “ wholly or partially enclosed in bone.” 
Subfamily : — SILUKID.® STENOBRANCHI.®. 
Grodp ; — Doradina. 
Ageniosiis militaris. 
There is a brief reference to the air-bladder of this species by Johannes Muller 
(28, fig. 10). The organ is said to be enclosed within a small osseous capsule formed 
by the “ first ” vertebra, which is open laterally, but divided in the median line by 
a bony partition wall. Two free blind diverticula from the bladder emerge posteriorly 
through two small apertures in the capsule. 
From the division of its capsule into two cavities by an osseous partition, which is 
probably the centrum of the complex vertebra, it is highly probable that the air- 
bladder of Ageniosus is also constricted longitudinally into two laterally placed 
air-sacs, as in such forms, for example, as Bagarius, Callomystax, &c. The descrip- 
tion is, however, too meagre to admit of detailed comparison with other types, but it 
may, nevertheless, be inferred, first, that the air-bladder of Ageniosus represents an 
abnormal and degenerate type, and secondly, that it bears a singular resemblance to 
the air-bladder of certain Cyprinidae {e.g., Botia) in which the partially atrophied 
posterior section of the organ is free in the abdominal cavity, while the anterior is 
more or less completely enclosed within a bony capsule. 
Auchenipterus nodosus. 
The only reference to the air-bladder of this species that we have been able to 
discover is by Johannes Muller. In a section of his valuable memoir (28) entitled 
“ Ueber einen Springfeder-apparat zur Erweiterung der Schwiinmblase bei raehreren 
Gattungen der Welse,” Muller includes Auchenipterus among those Siluridse that 
possess a peculiar “elastic spring” mechanism for the compression of the air-bladder, 
the importance of which he was the first to recognize, although Valenciennes had 
previously referred to its existence in his description of the skeleton of Synodontis. 
In figs. 5 and 6, Plate 3, of the memoir (/.c.) the “ elastic spring ” apparatus and its 
relation to the air-bladder are figured. 
Ihe centrum of the first vertebra (fig, 59, v') is much smaller than the centra of 
any of the normal vertebrae, but is nevertheless freely exposed both in the floor of the 
neural canal and externally on the ventral surface. The complex and three succeed- 
ing vertebne are rigidly anchylosed together by the partial coalescence of their neural 
