140 MARINE AND FRESHWATER FISHES 



FAMILY XXIIL RIBBON-FISHES (Trachypterida). 



Body elongate, compressed, riband-shaped, devoid of 

 scales ; dorsal fin extending the whole length of the 

 body ; anal fin entirely wanting ; caudal fin absent, or if 

 present, rudimentary, and developed at an angle diverging 

 from the normal longitudinal axis ; branchiostegal rays six 

 in number. 



The Ribbon-fishes, represented by two British species, the 

 Deal-fish, or Vaagmaer (Trachypterus arcticus\ No. 83, and 

 Bank's Oar-fish, or Ribbon-fish (Regalecus Banksii), No. 84, 

 are rare forms, inhabiting the deeper, colder waters of the 

 ocean, diseased or disabled specimens only being at long 

 intervals found floating helplessly on the surface or cast 

 upon our shores. Both species are remarkable for the 

 relative thinness of their compressed bodies, whence their 

 name of Ribbon-fishes. Bank's Oar-fish, more especially, 

 attaining to a length of from sixteen to twenty feet, yields no 

 more than from two to three inches as its greatest thickness. 

 Casts of a fine example of this species, captured at Dunnett 

 Bay, Caithness, in July, 1877, as also of a shorter specimen 

 from the Mediterranean, will be found in the Buckland 

 Museum. In both instances, unfortunately, the very slender, 

 oar-like pectoral fins and crest-like elevated rays at the 

 commencement of the dorsal fin had been removed or lost 

 at the time of capture. The development of these elongated 

 appendages would appear to vary at different ages, and 

 probably in connection with the separate sexes. The fish 

 known as Hawkin's Gymnetrus, figured erroneously in 

 Buckland's "British Fishes" as possessing a large fan- 

 shaped tail the caudal region was actually wanting in the 

 type when stranded near Penzance and four pedunculated, 

 paddle-shaped ventral rays, is now generally regarded as 



