WHICH HAVE NEVER DESCENDED TO THE SEA. 451 



Much of the foregoing seems to me simply hearsay evidence, and several points require 

 elucidation. First, did any stream flow into these ponds ? and, if so, of what size ? or were 

 they more or less stagnant pieces of water ? Secondly, did suitable food exist in hese ponds, 

 or were the fishes fed ? Thirdly, how was it ascertained that no spawn was deposited 



Respecting this last question, a very interesting observation was made by Mr. 0. L. 

 Jackson, Honorary Naturalist to the Southport Aquarium (« Land and Water, June 10th, 

 187G) that the « Salmon-trout cast their ova in the salt water in the Southport Aquarium 

 without assuming the appearance of kelts or even leaving off feeding greedily on 

 shrimps. They did not attempt to make a bed, and the spawn was immediately eaten 



bv their fellows." . „ , , 



It will now be necessary to follow out briefly the different stages of growth of the* 

 fish whieh occurred during the several changes from parr to smelts or grilse. Dr. J. 

 Davy says' « that parr put into a pond from whieh they could not escape, have grown 

 in two or three years to he about half a pound in weight, and when caught were 

 found to be in excellent condition, end still retaining their original transverse markings. 

 He also (I.e. footnote p. 220) remarks :-« The milt of the young fish, so far as 

 have observed, is always shed before the parr becomes a smot." It seems cvifleu 

 from the foregoing that by parr he did not intend to include silvery smelts with pan- 

 bands ; and if such was bis meaning, it is not in accordance with the changes shown by the 

 parrs and smelts at Howictoun, where ttsh in the smelt t livery gave milt; and the seme 

 series of experiments have shown that individual variations in size among these 

 artificially reared, and under identical conditions, can neither be due to the age of the 

 parents nor the character of the stock from which the ova or milt has been procured 

 P A Committee of the Tay Proprietors, on May 2nd, IW, was held at the S —he d 

 ponds, •■ to consider the expediency of detaining the fry [winch had been hatched Mare 

 31st, 851, end were 3 or I inches in length] for another year or allowing then to 

 depart A comparison with the undoubted smelts of the river then descending seaw aids 

 with the fry in the ponds, led to the conclusion that the latter were net yet smolts, and 

 ought to ie detained. Seventeen days afterwards, viz. on the 19th May a second 

 mental was held, in consequence of the great numbers of the fry having in he interim 

 Is umeu "he mig atory dress. On inspection, it was found that a considerable portion 

 w Tactual smolts, and the Committee came to the determination to allow them .to depart 

 Accordingly, the sluice communicating with the Tay was opened, and every am My to, 

 ITS" afforc led. Contrary to expectation, none of the fry manifested any mclmataon to 

 eav 1 fpond until the 2«h of May, when the larger ami more mature of the smolts, after 

 having held themselves detached from the others for several flays went off in a body. 

 II, -reset similar emigrations took place, until fully one half of the fcy had left the 

 poifl and deseenflefl the' sluice to the Tay. ... as the shoals successively left the pouch 

 ibmit one in every hundred was marked by the abscission ot the second dorsal flu A 

 Later number were marked on the 29th of May than on any other day, in all about 



* "Daw ' Physiological Researches,' p. 221. 



t S difficult in L, following description of the Howietoun experiments to separate the t-»™^» *£ 

 as these fish do not descend to the sea. on the first return from winch, m a normal condition, the, would be gnlse. 

 Anyhow, after the deposition of ova they may be termed grilse. 



