172 SALMONID^ OF BRITAIN. 



ever, is one of tliose broad assertions which require confirmation based on more 

 extended observation. In February, 1887, I examined a very large number of 

 young Lochleven trout at Howietoun, and found, as I shall subsequently have to 

 refer to, that they possessed from fifteen to seventeen cross-bands, some being 

 more or less broken up. But these bands are not invariably the same in number 

 every year, thus in 1884 I recorded in the Proceedings of the Zoological Society 

 (pp. 28, 29) how in eight young specimens of Loohlevens at Howietoun they varied 

 between eleven and fourteen, these being four pairs of young trout of the same 

 race raised in the same establishment and under identical circumstances, but 

 which had been some months in the ponds at Craigend in water from a different 

 stream. While in some undoubted young brook trout in Gloucestershire I have 

 observed from nine to eleven bars. In April, 1887, Mr. Andrews showed me his 

 beautiful young fish at Guildford, and among the Lochleven yearlings raised from 

 Hovrietoun eggs were numerous examples with eight, nine, ten, eleven, and a few 

 with thirteen cross bands. Also fifteen on a young local brook trout, but in these 

 the generality ranged from eight to eleven. Some of the alevins of both forms 

 showed an orange edging to the adipose dorsal fin, and on both margins of the 

 caudal. While in some yearling local brook trout and also in some similar 

 Loohlevens the amount of orange in the dead fin varied. In one yearling brook 

 trout there were three brilliant vermilion spots on the dead fin. If therefore 

 fresh- water trout can vary, as I have now instanced, in these marks between nine 

 and seventeen, the specific value of the number of such can hardly be great. 

 The adipose dorsal fin, although usually margined with orange in the smolt or 

 grilse stage, may be lead coloured.* 



Verteirce.f — As regards the number present in either race my information 

 from the examination of specimens is not so full as I could desire, because in 

 each case the fish had to be sacrificed. In salmon-trout I have observed from 

 57-60 -\- X and in sewin from 58-60 -)- x. Yarrell has recorded 58 for the salmon- 

 trout and 59 for the sewin, but he apparently rather mixed up his forms ; while 

 Dr. Giinther has given 8. trutta 69-60, 8. oamlricus 59, and 8. hrachypoma, which is 

 the grilse of the salmon-trout, 69. 



Varieties. — These are not very material unless it is considered that two distinct 

 species are included under the head of sea trout. In form — these may be 

 congenital or acquired, and as they are very similar to what obtain in the fresh- 

 water trout the two will be examined conjointly. In colour — these are various, 

 from silvery to being as spotted as a uiver trout, as wUl likewise be detailed. 



8exual distinctions. — The male has a knob, hook, or kype developed at the 

 upper surface of the end of the lower jaw and which has a seasonable augmenta- 

 tion in size during the breeding season, there is also a thickening of the skin, 

 especially along the back, as remarked on when describing the' salmon (p. 67 ante), 

 but in the sea trout ulceration through the upper jaw appears to be rare. 



Names. — These have already been referred to (see pp. 149, 160 ante). Bull 

 trout seems to be given to different fishes in various places. When netting the 

 Teith, the superintendent, the river watchers, and fishermen agreed that sea 

 trout attain to 6 lb., but are rarely larger : but bull trout of 20 lb. or 30 lb. are 

 seen and believed to be hybrids between the salmon and sea trout. It is quite 

 clear that old male salmon-kelts are not infrequently called " bull trout." In 

 some localities sea trout are termed gray trout. Mr. Congreve considered bull 

 trout sterile examples of this species which have ceased breeding and discontinued 

 their annual migrations, while their flesh may be either white or pink. 



* Dr. M'Intoih (Scottish Naturalist, 1872, p. 231) observed that " the reddish edge of the 

 fatty fin is most marked in the common trout, is present in a less degree in the ' yellow fin ' 

 (though in some scarcely noticeable) and is absent in the smolt. The blackish pigment at the 

 base of this organ is more developed in the 'yellow fin' than in the trout." While in its 

 fully developed migratory condition " the fatty fin, the dorsal and ventral and edges of the caudal 

 are generally bordered with red " (p. 230). 



t In counting the vertebrae, I adopted the advice given by an old author to boil the fish and 

 detach bone from bone, so as to be sure no mistake occurred in the enumeration. As already 

 remarked, I do not in the above count the last aborted vertebra. 



