ACANTHOPTERYGII. 125 



Gasterosteus, Cuv.(l) 



The cheek mailed, although the head is neither tuberculous nor 

 spinous, as is the case in the preceding genera. Their peculiar cha- 

 racter consists in the freedom of the dorsal spines, which do not 

 form a fin, and in the pelvis being united to humerals larger than 

 usual, and thus furnishing the abdomen with a sort of bony hauberk. 

 Their ventrals, placed farther back than the pectorals, are nearly 

 reduced to a single spine; there are but three rays to the branchise. 

 Some of them abound in the fresh waters of Europe. 

 Two species are confounded under the name of Stickleback, 

 Gasterosteus aculeatics, L.j which have three free dorsal spines; 

 but the entire side of one of them, G. trachurus, Cuv. Bl., pi. 

 53, f. 3, is covered with scaly plates to the very end of the tail. 

 These plates are only found in the other, G. gymnurus, Cuv. 

 Willughb., 341, on the pectoral region. Both these species are 

 sometimes so abundant in certain rivers in England and the 

 north of Europe, that they are used to manure the land, feed 

 hogs, &c.(2) 



G. pungitius, L. ; BL, 53, 4, is the smallest of the European 

 fresh water fishes; nine very short spines on the back; sides of 

 the tail with carinated scales; another closely allied species in- 

 habits the same streams, G. laevis, Cuv., in which this armature 

 is wanting. A separate subgenus might be made of the 



G. spinochia, L.; Bl., 53, 1, a salt water species of an elon- 

 gated and slender form, with fifteen short dorsal spines, and the 

 entire lateral line covered with carinated scales. Its abdominal 

 shield is divided in two; and, besides the spine, there are two 

 small rays in the ventral. 



After this family we place the 



Oreosoma, Cuv. 



A small oval fish, whose whole body, above and beneath, is studded 

 with thick cones of a heavy substance. There are four of them on 

 - J - 



(1) N.B. This name, which signifies bony belly, is only applicable to the Gas- 

 terostei as we have defined them, and not to several of the Scomberoides, united 

 with them by Linnaeus on account of their dorsal spines being free: these latter we 

 refer to our Lichia. 



(2) Neighbouring species or three-splned Sticklebacks; G.argyropomus, Cuv.; 

 G. braehycentrus, Cuv.; G. tetracanthus, Cuv., three Italian species; G. nove- 

 boracensis, Cuv.; G. niger, Cuv., or bicukat us, Mitchill, Ann. New York Lye, I, 1, 

 10; G. quadraius, Id., lb., f. 11; G. caiaphradus. Tiles. Mem. Acad. Petersb., 

 Ill, viii, 1. 



