Classijication of some Tdeoslean FisJies. 5 



North Atlantic and Japan, has the dorsal, with IV 3 3-19 

 lays, much shorter than the at'al, which lias IIl-IV 26-30; 

 the pelvics have I 10-13 lays. The latter includes three 

 recent species from South Australia atid New Zealand, in 

 which the dorsal, with VI-VII 12-14 rays, is longer than 

 the anal, which has IV 12-15, whilst the pelvics have I 7 

 rays. Moreover, the spines are stouter than in Beryx, and 

 the scales are larger and structurally different, being slightly 

 rugose with strongly pectinated edges, instead ot covered 

 with little spines. There are several Cretaceous species of 

 Hoplopteryx ; in the Australian H. affinis, Giinth., the crests 

 and ridges on the head are arranged exactly as in the 

 Cretaceous H. lewisiensis described and figured by Dr. Smith 

 Woodward. I give a figure of H. affinis^ for comparison with 

 the extinct forms (PI. I.). 



Family 4. Diretmidae. 



The type of Diretmus argenteus, Sohnson, is in the British 

 Museum collection ; it is evidently related to the Berycidae. 

 The dorsal and anal fins appear to be formed mainly of 

 articulated rays, and probably not more than 3 or 4 are 

 spinous ; the caudal has 17 branched rays ; each pelvic fin 

 is composed of a laminar, oblong ovate, obliquely striated 

 spine and 5 branched rays ; (the pelvic spine of Beryx is 

 obliquely striated) . The scales are small, adherent, spinulose, 

 differing from those of Beryx in that the bases of the spinules 

 are expanded into parallel vertical ridges. 



The jaws have narrow bands of villiform teeth, with a series 

 of larger pointed teeth in the lower; the palate is toothless. 



The single large supramaxillary has the form of the 

 posterior supramaxillary of the Berycidai ; the nasals are 

 separated by the prffimaxillary processes; the subocular shelf 

 and the alisphenoids and orbitosphenoids are as in the 

 BerycidEe. The cranial crests and ridges are as in the Bery- 

 cidse, except that the paired ridges which converge forward 

 from the parietal crests in the latter are now united to form 

 a single median ridge, owing to the narrowness of the inter- 

 orbital region. The thin-walled auditory bulla containing a 

 large otolith can be seen above the gills. The pelvic bones 

 are embraced by the enormously expanded hypocoracoids, 

 which meet in a long symphysis ; this is an exaggeration of 

 the Berycid condition. 



Family 5. TrachichthyidaB. 

 Dorsal and anal spines few; pelvic fins thoracic, of a spine 

 and 6 soft rays. Jaws and dentition as in the Berycidte, but 



