SCIENTIFIC SURVEY. 



83 



Sub-class Teleostei. Gasterosteoid^. 



trils large and placed half way between eyes and point of the jaw. 

 A broad silvery plate back of the gill opening. Body somewhat 

 oblong, compressed, and very slender at the base of the tail. 



It is covered with twenty-eight or thirty bony plates, narrow 

 and plated vertically, with slight serratures on their posterior mar- 

 gins and with perpendicular striae or markings. It is of a green 

 color above and silvery below. 



Lateral line pretty high up. It has the power of raising or de- 

 pressing the spines on the back ; the dorsal is longer than it is 

 high. The forward rays longest, one spine and twelve soft rays ; 

 pectorals fan-shaped. Two sharp serrated spines stand in the 

 place of the ventrals, and between them is a kind of bony lance- 

 shaped plate, rough upon its surface, serrated on its edges and on 

 central keel. It seems to be made for a support to the abdominal 

 point wMch is anterior to the vent. 



Anal fin commences on a line a little posterior to the dorsal, and 

 ends on a line with its own preceded by very minute spines. 



Caudal fin is very slightly emarginate and has twelve rays. 



Kay formula — 



D. 2, 1, 11; P. 10; V. 1; A. 1, 6; C. 12. 



Length .two and a half inches. 



Gasterosteus DeKayi, Agassiz. 

 Many Spined Stickleback. 



This little fish is an occupant of both fresh and salt water, often 

 in the brackish water about salt meadows. It has more than 

 seven spines in front of its dorsal fin. 



Specific description. The head of this species is small, about 

 one-fifth the length of the body. Gape of the mouth obliquely 

 downward ; nostrils round, and near the orbit ; jaws full of small 

 teeth. The opercula are of a silvery color ; eyes circular black, 

 iris metallic. 



Body is elongated, a little compressed, and tapers gradually from 

 the dorsal. Upon the back there are generally ten sharp, slightly 

 curved spines, inclined from right to left. The first are placed 

 midway between the operculum edge and dorsal fin. 



The dorsal is of a triangular shape ; has ^e stout spine and 

 seven soft ones ; anal beneath dorsal and like it in shape, with four 



