492 



ANATOMY OF VERTEBRATES. 



326 



Air-bladder, Corvina 

 trispinosa 



altipennis, Lactarius delicatulus). Corvina trispinosa, fig. 326, has 

 two slender ciecal processes from each side of its air-bladder; the 

 Bearded Umbrina has three such processes ; the 

 allied ' Maigre ' and other species of Scicena, 

 with most of the Corvinm, have very numerous 

 lateral pneumatic creca, which, as in Johnius 

 lobatus, fig. 327, are more or less ramified. 1 In 

 some species of Cheilonemus and Gadus blind 

 processes are continued from both the sides and 

 ends of the air-bladder (see the anterior ones 

 in Gadus callarias, fig. 321, A, p). In Gadus 

 Navavaga the lateral productions expand, and 

 line corresponding expansions or excavations of 

 the abdominal parapophyses, thus foreshadow- 

 ing the pneumatic bones of birds. In Kurtus the 

 air-bladder is encircled by expanded ribs, curving 

 and meeting below it. 2 



The proper walls of the air-bladder of ordi- 

 nary Osseous Fishes consist of a shining silvery 

 fibrous tunic, the fibres being arranged for the 

 most part transversely or circularly, and in two 

 layers fig. 229, a r; they are contractile and elastic; but 

 the walls of the anterior compartment of the air-bladder of 

 Cyprinoids, ib. p, are much more elastic than 

 those of the posterior one. The air-bladder 

 is lined by a delicate mucous membrane, with a 

 ' plaster epithelium ; ' it is more or less covered 

 by the peritoneum. Its cavity is commonly 

 simple ; in the Sheat-fish it is divided by a 

 vertical longitudinal septum along three-fourths 

 of its posterior part. 3 The lateral compart- 

 ments are subdivided by transverse septa in 

 many other Siluroids (e. g. genus Bagrus) : the 

 large air-bladder of some species of Erytlirinus 

 (e. g. E. salvus, E. tceniatus) is partially subdi- 

 vided into smaller cells. The cellular subdivi- 

 sion is such in the air-bladder of the Amia, that 

 Cuvier compared it to the lung of a reptile 4 ; 

 Air-wadder, johnius lobatus and the transition from the air or swim-bladder 



1 xxxix. i. p. 94, after Cuvier and Valenciennes, xxill. pi. 138, 139. The most 

 complex form is that described by Giinther (clxxiv, vol. ii. p. 313) in Cullichthys 

 lucida, where the air-bladder forms a second investment of the abdominal viscera, 

 within the peritoneum. 



- clxxiv. vol. ii. p. 10. 3 cxvi. vol. ii. p. 33, pi. 6, fig. 4. l xxiv. vol. ii. p. 377. 



327 



