ORIGIN, SYSTEMATIC POSITION 5 



Cunningham (1897, p. 498) was the first to throw doubt on the vaUdity of associating 

 the Flatfishes and Gadoids, remarking that " there can be no doubt that the Gadids 

 and Pleuronectidae, instead of being closely allied, are very remote from each other in 

 structure and descent ". Subsequently, Boulenger (1902) and Regan (1910B) have 

 produced good reasons for the separation of the two groups. The Heterosomata and 

 Anacanthini agree in having the mouth more or less protractile and bordered above 



Fig. 5. — Gadus callarias. a, Dorsj 

 and pelvic bone, d, Posterio 

 Figs. 2 and 3. (X J.) 



part of vertebral column and < 



of skull, 

 ludal fin 



c, Pectoral arch 

 Lettering as in 



by the praemaxillaries alone ; the parietals are separated by the supra-occipital ; 

 there is no orbitosphenoid ; the pectoral arch is attached to the skull ; and there is 

 no mesocoracoid. Comparison of the osteology of Psettndes with that of a generalised 

 Gadoid (Figs. 2, 3, 5), however, reveals the following important differences, among 

 others : (i) The spinous rays of the dorsal fin and the spinous first ray of the pelvic in 

 Pseltodes are wanting in the Gadoids ; (2) in Psettodes the pelvic bones are directly 

 attached to the cleithra of the pectoral arch, whereas in the Gadoids they are connected 



