3 6 ° 



TELEOSTEI 



posterior chamber ; in Otolithus a median chamber has paired lateral 

 prolongations (Fig. 349) ; in the Sciaenidae and Polyxenidae in- 

 numerable branching diverticula are given ort* (Fig. 3-48) ; in 

 ( 'allichthys the complication is still greater. The cavity of the air- 

 bladder is sometimes divided into compartments (Siluridae (p. 377)), 

 or small alveoli (Erythrinus). In the Herring (Fig. 383) a special 

 opening to the exterior is formed behind the anus (Weber) ; while 

 a communication is established with the right branchial cavity in 

 the physoclistous Caranx trachiuriis (Moreau). The bladder is a 



Fig. 346. 



A and 15, eye of Acanthias vulgaris, Risso. B and C, eye of Salmo salar, L. A and C, section 

 of eye vertical to surface, leaving the lens intact. B and 1), inner view of the outer half of the 

 eyeball, showing the lens in position. 1, lens ; - 2, cut surface of retina ; 3, retina ; 4, anterior 

 chamber or aqueous humour ; 5, posterior chamber or vitreous humour; 6, pigment layer ; 7, 

 cut edge of sclei i >i Lc ; 8, iris ; 9, ora serrata ; 10, optic nerve ; 1 l, cornea ; 12, ventral accom- 

 modating muscle (ciliary process) : 13, vascular ridge from choroid fissure ; 14, vascular process 

 (campanula Halleri). (Goodrich ami Gradon.) 



hydrostatic organ, is never supplied direct from the aortic arches 

 (p. 226), and never functions quite as a lung ; but on its inner Avail 

 are developed retia mirabilia, highly vascular patches, which secrete 

 the gases in the bladder (Hasse [199]). 



Caecal outgrowths towards the head and tail occur in a large 

 number of families (Berycidae, Siluridae, Clupeidae, etc.). A con- 

 nection between them and the ear is often established. In the 

 simpler cases a diverticulum on each side abuts against a 

 membranous fenestra of the periotic capsule, so that pressure or 

 vibrations can be communicated from the bladder to the perilymph 



