DACTYLOPTERUS. FISHES. 469 



Gen. 90. DACTYLOPTERUS, Lacep. Trigla, Lin. 

 Detached rays below the pectoral fin numerous, and united by 

 a membrane, so as to form distinct pectorals ; rays of the su- 

 pernumerary pectorals as long as the body, forming a species 

 of wings ; snout short ; occiput and preoperculi prolonged 

 behind into long spines ; jaws with small rounded teeth ; 

 scales carinated. 



D. volitans, Cuv. Body crimson-red above, whitish beneath, cover- 

 ed with strong carinated and sharp-pointed scales ; first dorsal fin 

 pale-violet, crossed by deeper lines, the two first rays separate 

 and longest j supernumerary pectoral fins very large, transparent, 

 olive-green, with numerous bright blue spots ; tail pale violet. 

 12 inches long. Inhabits Mediterranean, Indian, and Atlantic 

 seas Shaw, iv. pi. 91. 

 This species is capable of supporting itself out of the water in the manner of the 



common flying-fish for some seconds, by means of its large pectoral fins. 



Gen. 91. CEPHALACANTHUS, Lacep. Gasterosteus, Lin. 

 Head furnished on each side with two dentated and very long 

 spines ; ho isolated rays before the first dorsal fin ; fins of or- 

 dinary proportions. 



C. Spinarella, Lacep. The only species known. Inhabits the In- 

 dian seas. Shaw, iv. 608. 



Gen. 92. MONOCENTRIS, Schn. 



Body short and thick, entirely mailed with enormous angular, 

 sharp, and carinated scales ; first dorsal fin composed of four 

 or five free spines, and the ventral fins of one, in the angle of 

 which are some soft rays ; head short, thick, mailed. 



M. carinata, Schn. Forehead projecting ; mouth large ; teeth 

 small, crowded ; eight rays in the branchial membrane. 5 inches 

 long. Inhabits Japanese seas Shaw, iv. 610. 



Gen. 93. COTTUS, Lin. 



Head thicker than the body, spinous, and flattened horizontal- 

 ly ; first dorsal fin spinous, distinct from the second soft one ; 

 pectoral fins large ; ventral fins thoracic. 



The fishes of this genus are found on rocky shores, can live for some time out of 

 the water, and, when irritated, inflate their head by filling their gills with air. The 

 fresh water species have the head almost smooth, and only one spine at the preoper- 

 culi. 



C. gobio, Lin. River Bullhead. Body yellowish-olive, deepest on 

 the head and back, variegated with black ; a hooked spine on 

 each side of the head. 3^ inches long. Inhabits clear rivers of 

 Europe. Penn. Brit. Zool. iii. pi. 43. 



C. quadricornis, Bloch. Four-Horned Bullhead. Head thick, 

 flattened below ; body olivaceous, marbled with brown above, 

 whitish beneath, with four bony tubercles on the head ; ventral 



