284 



LOWER VERTEBRATES. 



are chiefly denizens of tropical seas. Little is known of their habits. The Fistularia 

 tabaccaria is perhaps the most common species. 



Several species of more compressed scaly fishes, with many weak dorsal spines, 

 constitute another family — Aulostomidje — closely related to the preceding. 



A species of Hemibranch, known on the English coast as snipe-fish, is the type of 

 another family, called CbnteiscidjE, or Maceoehamphosidje. Its representatives 

 have a comparatively short sub-ovate body, covered with bony plates in front, and 

 especially about the back, an elongated tubiform mouth, ventrals about the middle of 

 the abdomen, with a spine and seven rays each, and a small distinct spinous dorsal 



Fig. 158. — MacrorliampliosiLS scoiopax^ snipe-fish. 



about the middle of the body. The type, Macrorhamphosus scolopax better known 

 as Centriscus scolopax, is quite a common fish in the European seas, and one speci- 

 men of it has been found on the Massachusetts coast. It is called by the English 

 snipe-fish and woodcock-fish. 



The only remaining fishes of the order of Hemibranchs are of a very curious type 

 known as the family Amphisilid^. These have the body excessively compressed and 

 diaphanous, and the caudal portion is much abbreviated and deflected downwards by 

 the encroachment of the dorsal cuirass over the dorsal *fin ; still further, this cuirass 

 is composed of plates connate with the ribs, the lateral ones being developed in con- 

 nection with the ribs; the head is produced into an elongate tubiform snout; the 

 ventrals are abdominal, and there are two dorsals crowded upon the downward-bent 

 tail. The species are confined to the Indian and Pacific oceans. 



