224 SALMONID^ OF BRITAIN. 



enumerating some which I have counted in examples of this fish. Among males 

 I have found them as follows : — In specimens varying from ? to 20| inches in 

 length : At Howietoun, among fertile fish 8 examples averaged about 67 ceecal 

 appendages, being one of each of these numbers — 82, 75, 74, 73, 65, 62, 62, 48. At 

 Cowley, in Gloucestershire, one fertile male had 62, one which was sterile 52. 

 Among females the number among fertile fish varying in length from 12 to 3'2 

 inches : 7 examples averaged about 58 of the appendages, being one of each of 

 the following numbers — 66, 64, 62, 59, 57, 55, 45, while one large female from 

 Loch Leven had 47, another 57. As a rule the size of these CEBca in females 

 appear to be larger than is seen in the males, while in one of the latter a single 

 one of these tubes was abnormally shortened near the pylorus. 



The foregoing figures show a variation of these appendages at Howietoun 

 from 45 to 82 in male fish, and from 45 to 66 among female fish ; while in one 

 fertile male which was examined in Gloucestershire, there were 62, and in 

 another, not so well fed, from the same locality, and sterile, there were 52. In 

 only one do we see the numbers approaching to 90 (82) as given by Dr. Giinther, 

 and with that exception 75 were the greatest amount counted, and from that 

 down to 45, clearly showing that this is an unstable character, prone to change, 

 and consequently unsuitable for characteristics wherewith to discriminate species. 

 Also, that, away from Loch Leven, these appendages have diminished in number, 

 and still more so in those from the ova hatched at Guildford and reared in 

 Gloucestershire, where likewise the smallest fish were sterile, and had the fewest of 

 these appendages. As to the difference in the diameter of these cseca such was 

 not usually apparent, except so far as I have mentioned above. 



Having thus seen that in its external form either the differences which have 

 been stated to exist between this fish and the brook trout are erroneous, or else 

 they are liable to alteration when the fish is removed to another locality, I think 

 all must admit that such unstable difEerences are insufficient for the purpose of 

 constituting species. 



As to external colour we find Parnell asserting as among its specific characters, 

 " body without red spots ; " and that these fish are generally seen without these 

 up to a certain age is of very common occurrence. The alevins and young par 

 raised at Howietoun are very similar to the young of the bum trout, but are 

 normally wanting in any orange to the adipose dorsal fin, it is rare for the 

 dorsal, ventral, or anal to be margined with a white, black-based edge, and the 

 par bands are mostly more numerous, sometimes being from 16 to 17. As the 

 fish become older three main types of colour are observable, a slaty or greenish 

 gray, becoming lighter beneath, and the upper two-thirds of the body and dorsal 

 fin spotted with black, and the fins generally grayish black. This form of colour 

 is prevalent up to the end of the fourth season, and may almost be looked upon 

 as equivalent to the silvery stage of the salmon smolt, or grilse,* but I have never 



collection as follows : — " Females, from 12 to 18 inches long. Purchased, said to be from Loch 

 Leven. Caught in April. Cffioal pylori 65, 63, 60, 54, 54, 53, 49 ; vertebrse 58-69. These 

 specimens have the pyloric appendages fewer in number than is generally stated ; yet these caeca 

 are so wide — so much wider than in S. fario, that the reduction of their number has evidently 

 been caused by a confluence of several C£eca with one " (Catal. vi, p. 101). 



From the foregoing it is evident that the number of these appendages is very variable, for in 

 this race they have been recorded as being from 45 to 90. If, however, we turn to the writing of 

 most authors that have counted those existing in the S. fario, we find them enumerated as follows : 

 — " I have never found them to exceed 46 " (Parnell, p. 808). Thompson in 1836 examined 

 the so-called S. ferox, and found in four examples 49, 45, 39, and 36 {Nat. History of Ireland, 

 iv, p. 157). Giinther among his other five non-migratory fresh-water forms enumerated them as 

 varying from 83 to 49. While Sim as already observed found them in 52 examples of Aberdeen- 

 shire and Kincardineshire specimens of burn trout to vary between 30 and 69. (See also p. 216.) 



* On September 8th, 1885, captured with a fly from one of the Howietoun ponds, a two-year-old 

 male Lochleven trout, the young of the 1875 fish, or one generation removed from those of Loch- 

 leven. Length 7-4 in., of head 1'6 in., diameter of eye 0-3 in., its distance from the end of the 

 snout 0.4 in., and 0-5 in. apart. CsBoal appendages 73. Colours — silvery with black spots which 

 are largest on the head and operoles where they are encircled by a light ring. Dorsal fin very 

 spotted, and with a dark upper fore-edge with traces of white ; front margin of anal the same. 

 Other fins grayish. Maxilla reaches to beneath the hind third of the eye. 



