WHICH HAVE NEVER DESCENDED TO THE SEA. 459 



I have already shown that the fact of parr having milt prior to descending seawards 



iaS been generally recognized, but that smolts or grilse kept under similar conditions 



m ve been almost always on the contrary declared not to give ova. But now we ha. 



he experiments made at Howietoun to consider, and these have undoubtedly proved 



hat young male and female Salmon kept in suitable freshwater ponds may develop 



M or ova. These fish were hatched in March 1881, and most of the male parr had milt 



in November 1883, or when 2 years and 8 months old; also two or three smolts of the 



.amea^e had ova which probably would have matured, but they jumped out of the pond 



nTso met with their deaths. In November or December 1881, or at 3 years and 8 



f 9 Tenths' age, all these fishes seemed to be ready to breed, and it appears 



obabTethen that' Salmon-parr do not possess milt for the purpose o nupregn. mg 



the ova of the old Salmon, or "to mingle with the River-Trout, a Dr Gunthe 



su^ests but to be ready to fertilize the eggs of any ascending grilse, for in some 



Sties' the"! latter deposit their ova prior to the usual period when adult male Salmon 



are present for breeding purposes. 



S„ m e authors bold that Salmon axe freshwater forms that proceed to , the sea, and that 

 there is a physiological necessity for their doing so in order to be able to .produce * 

 Other,, who I believe are more correct, consider these fish marine to - U a ascend 

 into fresh water to deposit their eggs and rear their young. As rt , eviden f« ■* 

 Howietoun experiments that these fish con give eggs without descending to salt water 

 fu i tToses'of the " physiological necessity- theory Possibly t bis imgra ion ma 

 be classed among the instances of "inherited instinct" and may *•«»»*. - 

 of Salmon as have been reared for a few generations in fresh water. I -may be that 

 in some such manner the "laud-locked Salmon" ot various "T^TL^ 

 originally differentiated from their fellows, an interesting instance of which I propose 



t0 „ll h O^e in 1S81 too, about 100 Sea-trout and Salmon smolts, which he 



turned into Loin* Ash, Co. Tyrone, which bas no access to the sea. April SO, 1SS3 he 



luir a gX 1 4 inches long in this lake, where Salmon had not previously been 



en Its ablomen was so distended that be considered it would have spawned very 



I^more especially as it was taken, £. outb of tbeon, stream that enteis 



Z netl ex^Tl TjT^t^L ■"*» «~ ^ ^ 

 S« iu "measured by me were each 0-25 of an inch in dieter. Proved 

 t, re'bad been a ripe male iu the vicinity, there seems no reason why this fish u 

 not have deposited her eggs, and such would thus have given rise to a land 



''""On the approach of autumn," observes Shaw (Trans Roy. Soc Edin ^ P. M* 

 footnote) "the whole of the Salmonids, resident as well as migratory, while in fresh 

 wato acquire a dusky exterior, accompanied by a considerable increase of mucus or 



* Described Tree. Zool. Soc. 1S84, p. 584. 



