THE ORDERS OF TELEOSTOMOUS FISHES . 499 



(Pleuronectid.se) or Flatfishes, but this association has been 

 shown by Boulenger to be wholly unnatural. The Anacanthini 

 differ from the Acanthopterygii chiefly in: (i) the lack of fin 

 spines in the vertical and ventral fins (the first dorsal of some 

 Macrurids has a single spiny ray); (2) in the feeble, ligamentous 

 attachment of the pelvic bones to the pectoral arch; (3) the 

 separation of the prootic from the exoccipital by the enlarged 

 opisthotic; (4) the loss of the primary homocercal tail (Appendix II,) 

 the caudal fin-supports of the seemingly homocercal tail of the 

 Gadidae being perfectly symmetrical above and below the 

 vetebral axis and composed mainly of dorsal and anal rays 

 (Boulenger 1 ); (5) the position of the scapular foramen, which 

 lies between the hypercoracoid (scapula) and hypocoracoid 

 (" coracoid"), instead of perforating the hypercoracoid, as in 

 most other Teleosts. However Tate Regan has shown that in 

 one of the Macruridae the position of this "scapular foramen" is 

 normal. As in the typical Acanthopterygii the parietals are 

 separated by the supraoccipital, the toothed premaxillaries 

 alone enter the upper margin of the mouth, the maxillaries simply 

 acting as levers for the protrusion of the mouth, the air bladder 

 is without open duct, the ventral fins are below or in front of the 

 pectorals. 



Of the two principal families, Gadidae and Macruridae, the 

 Macruridae are believed by Tate Regan and Boulenger to be, on 

 the whole, more primitive. "In the Macruridae we pass from 

 the more generalized forms with cycloid scales, terminal mouth, 

 and continuous or subcontinuous dorsal fins, to those with 

 rough or spinous scales, inferior mouth, and projecting snout, and 

 a well differentiated anterior dorsal " (Tate Regan). Among the 

 more central Macrurids the genus Macruronus closely resembles 

 Merlucius of the Gadidae in its skull, but is "a true Macrurid 

 in the position of the ventrals and the absence of a caudal 

 fin" (Tate Regan). In the Gadidae the scales are reduced, the 

 dorsal and anal fins are often divided into two or three portions, 

 and a secondary fan-like tail is formed from the dorsal and 

 anal fins. As to the derivation of the order, whether from 

 true Acanthopterygians or from some less specialized stock, such as 



i Ann. and Mag. Nat. Hist. (7) Vol. X. Oct., 1902, p. 298. 



