474 



TELEOSTEI 



to the ocular side. Owing to the forward growth of the anal fin, the 

 radials of which meet the haemal arches, the abdominal cavity becomes 

 excessively shortened, and the viscera may extend backwards on either 

 side in blind coelomic diverticula (Solea}. The pyloric caeca may be 

 absent. The scales are cycloid or ctenoid. The vertebrae, twenty-four 

 in number in Psettodes, may be much more numerous in higher genera. 



FIG. f>03. 

 Solea heterorhinc, Blkr. (After Day, Fishes of Iiul'tu.) 



Concerning the asymmetry it is interesting to note that in Psettodes 

 the eyes may be either on the right or on the left side ; while in some 

 genera like Hippoglossus, Pleuronectes, and Solea, they are on the right ; 

 and in others, like Psetta, Arnoglossus, and Cynoglossus, the left is the 

 ocular side. Always there is a difference in colour between the two 

 sides, the lower being white and the ocular strongly pigmented. 



FIG. 504. 

 Hynaptum albomvciilutct, Kp. (After Day, Fidies of India.) 



(Psetta} Rhombus, Kl. ; N. Atlantic, Mediterranean; and Eocene. Solea, 

 Cuv. (Fig. 503) ; wide range, Miocene. Psettodes, Benn. (Fig. 502) ; 

 Ammotretis, Gthr. ; Achirus, Lac. ; Hippoylossw, Cuv. ; Pleuronedes, Art. ; 

 Citharus, Blkr. ; Rhomboidichthys, Blkr. ; Arnoglossus, Blkr. ; Zeugopteru*, 

 Gotzsch; Synaptura, Ctr. (Fig. 504) ; Cynoylossus, H. B. ; Sympknrus 

 (Plagusia) all marine. 



