148 ORDER ACANTHOPTERYGII. 



which are hidden some soft rays almost imperceptible. 

 Their head is thick and shielded ; their front swollen 

 out ; the mouth rather large ; the jaws and palate 

 have close even teeth, but the vomer is without them. 

 There are eight rays to the gills. 



Only one species is known, proper to the Japan 

 Seas. 



Monocentris Japonica, Bl., Sch. pi. xxiv. 

 Six inches long, and silvery white '. 



Gasterosteus 2 , Cuv., 



Have also the cheeks shielded, although their head 

 is neither tuberculous nor spiny, as in the preceding 

 genera. Their particular character consists in having 

 the dorsal spines free, and not forming a fin, and 

 also in having the pelvis united to humeral bones 

 larger than common, furnishing the belly with a sort 

 of bony cuirass. Their ventral fins are placed behind 

 the pectoral, and are reduced almost to a single spine ; 

 there are only three rays to their gills. 



We have some of them which are very numerous 

 in our fresh waters. 



1 Gasterosteus Japonicus, Houtt. Mem. de Harl. xx. second part, 

 299, or Sc'icena Japonica, Thunb. Nouv. Mem. de Stock, xi. 3. copied, 

 Bl. Schn. pi. xxiv. 



1 This name, which signifies bony belly, agrees with the Stickle- 

 backs, (Gaslerostei) such as we define them, and not with many fish 

 of the scomber family, which Linnaeus placed with them, because 

 their dorsal spines are free. These we transmit to our genus Lichia. 



