EEPORT ON THE DEEP-SEA FISHES. 45 



wide, obliquely ascending, with projecting lower jaw. The jaws are armed with 

 a very narrow band (which, posteriorly, becomes a single series) of small fine teeth of 

 unequal size. The vomer and palatine bones are toothless. The maxillaries terminate 

 at their ujaper and inner extremity in a pair of short pointed processes, which form 

 peculiar fang-like projections in the inside of the mouth, in front of the vomer. Bones 

 of the head thin, with wide muciferous cavities, the lower limb of the prseoperculum 

 denticulated. Eyes very large. Dorsal long, without spinous division ; anal similar in 

 form and composition ; interradial membrane very fragile. Pectorals large ; ventral fins 

 thoracic, with more than five rays (?). Branchiostegals seven ; pseudobranchiaj. 



To judge from external characters we may place this genus provisional!)' near Brama. 



Diretmus argentens. 



Diretmus argenteus, Johns., loc. cit., pi. xxxvi. fig. 1. 



D. 27. A. 22. P. 18. 



The specimen from Madeira, described in detail and well figured by Johnson, is still 

 the only one known. This author ascribes to it, although with doubt, ten ventral rays, 

 but the rays are much confused, liroken, and split down to the base, so that their exact 

 number cannot be ascertained. The spine is enlarged into a thin scalpel-shaped lamella, 

 and marked with numerous oblique striae. 



It is evident from the structure of the cranial bones, the immense eyes, the black 

 colour of the cavity of the mouth and pharynx, and also from the extreme scarcity of the 

 fish, that this species belongs to the deep-sea fauna. 



Diretmus aureus. 



Discu!' aureus, Campbell, luc. cit. 



D. 26. A. 21. P. 17. 



I should be inclined to refer this fish, \<'hich is known from four specimens, 2f inches 

 long, cast up on Hokitika beach (New Zealand), to the same species as the Madeiran 

 specimen, but for the seeming absence of the enlarged ventral spine. This, of course, 

 might also be accounted for by the less advanced age of the specimens. All the other 

 difierences as they appear in the description would probably disappear on a direct 

 comparison of the examples. The perforations of the iuterradial membrane of the dorsal 

 and anal fins, which Campbell regards as an extraordinary character, may also be seen in 

 the Madeiran type, and are due to the extremely delicate structure of the membrane. 



