Pelagic Fauna of our Shores. 143 



Thus it is found at a depth of 25 fathoms on 32-fathom 

 ground (^. e. about 7 fathoms from the bottom) as a little fish 

 having the form of the adult but with a pair of enormous 

 ventral fins (like those of the young sword-fish *) of a deep 

 yellow colour, the only remnant of the tint so characteristic 

 of the tadpole-stage. It would appear to be a truly pelagic 

 stage of a bottom fish, for it is doubtful if the long ventrals 

 would be of much use to an active fish that seeks its prey on 

 or near the ground. The other larval fish characterized by 

 long ventrals is the rockling f, and it is noteworthy that these 

 are likewise conspicuously coloured, being white at the base 

 and black at the tip. The rockling, like the ling, haunts the 

 bottom in adult life, while it is truly pelagic in its larval 

 stages. Too little is yet known in regard to the influence of 

 such elongate ventrals on the habits of these young fishes to 

 enable a correct judgment to be formed ; but it would appear 

 to be, in part at least, connected with tlieir more active exist- 

 ence. In the same way the huge pectorals of the larval 

 gurnard (which cause it to mimic the flying gurnard) can be 

 explained. An analogous condition is seen even in the pec- 

 torals of the larval catfish (in which, of course, ventrals are 

 entirely absent), and their tails are also proportionally larger 

 than in the adult, thus enabling them to mount readily through 

 a considerable stratum of water, though they are hatched ou 

 the bottom and ultimately live there. In estimating the 

 influence of such modified organs it is well to bear in mind 

 that at a later stage and with much shorter fins certain fishes, 

 such as the cod and haddock, procure similar (pelagic) food, 

 but at a distance from the surface and in the midst of difterent 

 currents. Their muscular systems, however, are much more 

 largely developed %. 



The special bearings of the wealth of pelagic life on the 

 nourishment of the young food-fishes now fall to be considered. 



* In this stage tlie little ling at first sight approaches the condition in 

 the forked hake, for which Mr. Calderwood and I for a moment took it. 

 The larval angler also shows huge ventrals, while in the adult they are 

 small. The dory, again, has long ventrals in its adult stage. 



t First pointed out by Alex. Agassiz in a form which he doubtfully 

 referred to Moteila argentea (Proc. Amer. Acad, of Arts & Sci. vol. xvii. 

 p. 294, pi. vii.). 



X Zoologists had been so accustomed to consider the greatest wonders 

 of the sea to be on the bottom that the novelties in the superincumbent 

 water had been somewhat under-estimated. Yet it is only in the latter 

 region that the mysteries still present in the life-histories of many of the 

 food-fishes can be unravelled and the direct and indirect influences exer- 

 cised by other pelagic forms on their growth duly appreciated. It is in 

 this connexion that the huge mid-water net attached to the large triangle 

 {vide Ann. & Mag. Nat. Hist, for Oct. 1886, p. 310) will be of real service 

 to science. 



