ii8 MARINE AND FRESHWATER FISHES 



highly interesting. The manner in which the Dory swims 

 by the rapid undulation of the soft dorsal and anal fins 

 only, referred to in the account given of the Boar-fish, was 

 recorded by the writer so long since as the year 1873,* the 

 only species of which a very similar mode of locomotion, 

 by means of the unpaired fins, had been hitherto observed, 

 being the Sea-horses and Pipe-fishes, belonging to the 

 Family Syngnathidce. As a rule, when undisturbed, the 

 Dory remains perfectly quiescent in mid-water in the 

 vicinity of the rockwork of its tank, and against which it 

 frequently leans for support. Like the Angler it is a 

 fish that captures its prey by stealth, and not by the 

 exercise of superior activity. That the Dory is a most 

 voracious feeder, is exemplified by the fact that as many 

 as twenty-five young Flounders and three half-grown Sea- 

 Bullheads have been abstracted from the stomach of an 

 example measuring only twelve inches and a half in its total 

 length ; while another Dory, weighing but I Ib. I oz., was found 

 to contain eighteen Sprats, two Sand-Smelts, and a Cuttle- 

 fish, with the remains of other species in a decomposed state. 

 When confined in an aquajium it is necessary to supply it 

 with living food, and in the case of those so kept at Brighton, 

 it was observed that the Dories either waited passively 

 until the fish provided swam sufficiently near as to be 

 engulphed by a single snap of their highly-extensile jaws, 

 or they approached them so slowly and stealthily by means 

 of the scarcely-perceptible vibratory action of the two 

 vertical fins, before referred to, that their advent was either 

 not noticed or viewed with unconcern, until, with the 

 rapidity of a flash of lightning, one or more victims in the 

 shoal had disappeared within the Dory's capacious mouth. 



* W. Saville Kent, " On Fish Distinguished by their Action." 

 'Nature,' July 31, 1873. 



