40 NORTHERN ZOOLOGY. 



range being to the Southern states, and some of them to the West Indies and 

 Brazils, it is not so likely that they go northwards beyond the influence of the Gulf 

 Stream. 



[10.] 1. Dactylopterus volitans. (Lacep.) Common Dactylopterus. 



Family, " Joues cuirassees " Genus, Dactylopterus. Cuvier. 



Trigla volitans. Linn. Le Dactyloptere commun. Cuv. et Val., iv., p. 120. 



The genus Dactylopterus differs from Trigla and its two sub-genera, Prionotus 

 and Peristedion, in the different shape of the helmet-like casing of the head, which 

 is long and broad, but flat and of small depth : the sub-orbitars do not project on 

 the sides of the snout, neither do they entirely cover the cheeks, while £he preoper- 

 culum is so connected with them, that instead of being entirely fixed, it retains 

 sufficient mobility to point its enormous spine, when required, as a defensive weapon : 

 the operculum is unarmed ; the teeth confined to the jaws are small, rounded, and 

 low, like paving stones (" dents en paves ") : there are only six branchiostegous 

 rays ; the ventral fins have only four soft rays (an unusually small number in Acan- 

 thopterygious fishes), and the supernumerary rays under the pectorals, instead of 

 being free, are united by membrane into a kind of parachute equalling the body in 

 length. The whole body is cased in large hard scales, which rise into longitudinal 

 ridges in various parts. 



The common species enters into our list as it occurs on the coasts of Newfound- 

 land. It ranges also through the seas of the United States, and is particularly 

 abundant in the Mediterranean, but does not appear to frequent the British Channel 

 or the Atlantic coasts of France. A second species exists in the Indian Ocean 

 and Archipelago. 



[11.] 1. Cottus cognatus. (Richardson.) Bear Lake Bull-head. 



Family, " Joues cuirassees." Genus, Cottus. Linn, et Cuv. 



The genus Cottus is characterised by a large depressed cuirassed head, variously 

 armed with spines or tubercles, a more slender, tapering, almost naked body ; two 

 dorsals either quite distinct or very slightly united ; ventrals of three or four rays 



