462 Mr. C. T. Eegan on tie 



vomerine and palatine teeth and a single continuous dorsal 

 fin. Lycomis, regarded by Dr. Giinther * as the type of a 

 distinct family on account of tlie undivided dorsal and the 

 presence of pseudobranchias, should also be placed in the 

 Macruridaj. ' 



In the Macruridae we pass from the more generalized forms 

 with cycloid scales, terminal mouth, and continuous or sub- 

 continuous dorsal fins, to those with rough or spinous scales, 

 inferior mouth and projecting snout, and a well-differentiated 

 anterior dorsal. In these latter the snout is formed by the 

 enlarged nasal bones, which unite in the middle line, and 

 are supported below by the united pra^orbitals ; in them also 

 the suborbitals are enlarged and angiilated, their upper portion 

 forming an oblique shelf supporting tiie eye. This feature 

 is most distinct in the genus Trachyrhynchus^ which repre- 

 sents the extreme of specialization, and in which the posterior 

 suborbitals extend back and join the prjeoperculum, and there 

 is no trace of a median suture between the frontals. The 

 post-temporal of Trachyrhynchus is also peculiar, as in 

 addition to the two forks which are attached to the epiotic 

 and opisthotic there is a third which runs to the exoccipital, 

 and the interspaces between all three are filled in by an 

 osseous membrane, so that it appears to form an integral part 

 of the skull, and has, indeed, been mistaken by Supino f for- 

 the opisthotic. 



Specialization witliin this family would seem to have been 

 accompanied by an increase in number of the pectoral pterygials, 

 for whilst Bathygadiis and Gadomus have three and Macru- 

 ronus four, in IlymenocephaJiis there are five, and in Macrurus, 

 CorypJicenoides, and Trachyrhynchus six. The extreme 

 inteiest of the genus Macruronus, represented by a single 

 species, M. novce-zealandice, has not yet been appreciated. 

 Although a true Macrurid in the position of the ventrals and 

 the absence of a caudal fin, it is at least as nearly related to 

 the Gadid genus Merluccius as to any member of its own 

 family (the evidently closely allied Steindachneria excepted). 

 The appearance of the head, with the wide terminal mouth, 

 strongly toothed jaws, &c., is exactly that of a Merluccius ; 



* * Challenger ' Deep-sea Fishes, p. loS, pi. xlii. 



t "Ricei-che sul Cranio dei Teleostei, II. Macrurus''' (Ric. Lab. Anat. 

 Univ. Rom. ix. fasc. 2-3, lii02). In this paper the sutures are not too 

 accurately depicted ; as has been said, the post-temporal is mistaken for 

 the opisthotic, and the large opisthotic has not been recognized. The uasal 

 bones are named " mesethmoid," and a pair of inferior frontal ridges 

 " orbitosphenoid." Moreover, I cannot find any trace of a basisphenoid 

 in this .species or in any fishes of this suborder. 



