32 THE VOYAGE OF H.M.S. CHALLENGEE. 



with thin bones and high ridges, between which large muciferous cavities are lodged. 

 Mouth very wide and oblique ; villiform teeth in the jaws, on the vomer and palatine 

 bones. Eye very large. Branchiostegals from seven to ten, gill-oi^enings very wide. 

 Prgeoperculum without spine. One dorsal fin with a few spines in front ; ventrals with 

 seven and more rays; pectoral asymmetrical; anal with four spines; caudal deeply 

 forked, with the upper and lower rudimentary rays transformed into spines. Air-bladder 

 simple ; pyloric appendages from twenty to thirty. 



Of the five species known of this genus two only are known to descend to such a depth 

 as to justify their admission into the deep-sea fauna. The other species (which belong to 

 the Australian fauna) seem to live habitually in shallower water, and not far from the 

 coast, where they are captured not unfrequently by the ordinary means. The two deep-sea 

 species are Beryx decadactylus and Beryx splendens ; they were discovered first in the 

 sea off Madeira, and more recently in the sea off" Japan. Lowe says that " the latter 

 species, the ' Alfonsin a casta cumprida ' of the Madeiran fisherman, begins to be met 

 with of small size at the depth of 150 or 200 fathoms, but is scarcely taken in full size 

 and plenty except with its congener, Beryx decadactylus, the ' Alfonsin a casta larga,' 

 at the depth of from 300 to 400 fathoms, and from one to two leagues from shore." The 

 Challenger Expedition obtained specimens of Beryx decadactylus only, off" Inosima, at a 

 depth of 345 fathoms, whilst we are indebted to H. Batson Joyner, Esq., for specimens 

 of Beryx splendens, which he obtained during his residence at Tokio. 



Young specimens have been found in the open sea. A specimen, described by Cuvier 

 and Valenciennes under the name of Beryx delphini, was taken from the stomach of a 

 Coryphsena in the Western Indian Ocean, in lat. 82° S. and long. 51° E. 



Eemains of extinct species of Beryx are found in Cretaceous formations, but not all 

 the species described as such belong to this genus or even family. The skeleton of Beryx 

 decadactylus, of which a figure is given on PI. VI., well illustrates the family charac- 

 teristics. 



On the whole the bones of the skeleton are solid and firmly built, but some of the 

 bones of the head are dilated into thin lamellar ridges, between which the muciferous 

 channels and cavities are lodged. This is particularly the case with the bones forming 

 the roof of the skull, the infraorbital ring, and the lower part of the mandible. The 

 canal running along the praeopercular limbs is much less deeply excavated. The basal 

 portion of the cranial cavity is comparatively short and deep, very much swollen to lodge 

 the organ of hearing and especially a pair of very large otoliths. The bones forming this 

 part of the skull are thin and perforated by an oblong opening between the alisphenoid 

 and basisphenoid, as in Myripristis} 



The vertebral column consists of eleven abdominal and thirteen caudal vertebrae. 

 The five anterior neural spines are remarkably stout and broad to support the anterior 



1 Cat. Fish., vol. i. p. 23. 



