PLEURONECTID^. 399 



Appendix to the AnacantJiim gadoldei. 



XENOCEPHALUS. 



Xenocephalus, Kaup in Wiegm. Arch. 1858, p. 85. 



Head very large, truncated, cuirassed with plates and armed with 

 spines ; body small. Only one dorsal and anal, separated from the 

 caudal by a small interspace. Vent in the posterior half of the body. 

 Small teeth Lq the jaws ; none on the vomer or the palatine bones. 



New Ireland. 



1. Xenocephalus armatus. 

 Kaup, I. c. p. 80. 



D. 7. A. 10. C. 20. P. 21. V. 5. 



Caudal fin large. Shields on the head yeUowish-brown, the naked 

 skin between them blackish. Body dark-brown, with black spots 

 on the back ; belly shining golden ; fins yellowish-white. {Kaup.) 



New Ireland. 



Fam. 7. PLEURONECTIDtE. 



Poissons plats, Ctcv. Regne A?nm. 

 Pleuronectidse, Fleiaing, Brit, Anim. p. 178. 

 Heterosomata, Bonapm-te. 



Body strongly compressed, flat, with one of the two sides, which 

 is always turned upwards, coloiU"ed, whilst the other is colourless 

 and only sometimes spotted. Both eyes are placed on the coloul6d 

 side ; and although the bones are present on both sides of the skull, 

 they are not equally developed or symmetr.^cl *. Dorsal and anal 

 fins exceedingly long, without divisions f. Gills four;'pseudobran- 

 chiae well developed ; air-bladder none. 



Carnivorous fishes, living on the sandy bottom of the coasts of all 

 the regions ; many ascend rivers. 



* This is unique in the division of Vertebrate animals. 



t A Pleuronectoid from the Pacific appears to form a remarkable exception, 

 having the dorsal fin composed of two portions differing in structure. However, 

 as this fish is known from a drawing only, we do not venture to propose a generic 

 appellation for it, and insert only the following abstract : — 



Hippoglossus kingii, Jenyns, Zool. Beagle, Fish. p. 138. pi. 26. 

 D. 18+48. A. 51. 

 The dorsal fin commences anteriorly to the upper eye, and its anterior eighteen 

 rays are much lower "tlian the following, apparently forming a distinct portion. 

 Eyes on the left side, rather distant from each other. The height of the body is 

 one-half of the total length (without caudal). Lateral line with a subsemicircular 

 curve above the pectoral. Uniform light brown. (Jen.) 

 Valparaiso. 



