ACANTHOPTERYGII 



655 



Fam. 1. Berycidae. — One or several of the suborbitals 

 emitting an internal lamina supporting the eye ; entopterygoid 

 present. Anterior vertebrae without transverse processes ; all or 

 most of the ribs inserted on the transverse processes where these 

 are developed. Two nostrils on each side. Gill-membranes free 

 from isthmus ; 4 to 1 branchiostegal rays ; gills 4, a slit 

 behind the fourth ; pseudobranchiae. Lower pharyngeal bones 

 separate. A'eiitral fins with 1 spine and 6 to 13 soft rays. 



Fig. 400 . — Bcryx splendens, J nat. size. (After Goode and Bean. ) 



This family is remarkable for the retention of two archaic 

 characters : the large number of rays to the ventral fins and the 

 duct between the air-bladder and the digestif tract ; the latter 

 character is, however, not universal, and has only been found in 

 two genera {Beryx and Holocentrum). The scaling of the body 

 varies greatly, and so does the development of the spines in the 

 vertical fins. Several genera {Melampluies, Anoplogaster, Trach- 

 ichthys, etc.) have the head studded with large muciferous cavities 

 which are covered with a thin skin. The vent is usually situated 

 far behind the ventral fin, but in Paratrachichthys, a genus 

 closely allied to Trachichthys, it occupies a more anterior position, 

 between the ventrals, whilst in Aphredoderus it shifts still further 

 with age, opening on the throat in the adult. 



The Berycidae were abundantly represented in Cretaceous 

 deposits by Beryx and other genera more or less closely related 

 to living forms^ and they appear to have been the precursors of 

 other Perciform Fishes. About 70 species, referred to 13 genera, 

 are known to live at the present day, mostly at great depths, m 



