SALMONID^. 93 



whicli latter fin is inserted under the middle or hind third of the first dorsal, and 

 extends above half-way to the origin of the anal. Caudal emarginate, becoming 

 square in large examples. Scales — there are 13 to 1-5 rows in an oblique line 

 running from behind the base of the adipose dorsal fin downwards and forwards to 

 the lateral-line, ocecal appendages varying in this species : Richardson found 73, 

 Parnell 80, Giinther 49 to 90, due either to several becoming confluent into one 

 stem, or one subdividing into several, but anyhow demonstrating inconstancy in 

 numbers. In a female example with the ova developing, the length of the fish 

 being 8 inches, received from Howietown in June, 1882, there were 47 ccecal 

 appendages, and mostly shorter than in the brook-trout : the length of the head 

 was 4 J in that of the total length. Colours — generally grayish or greenish along 

 the back, becoming lighter on the sides and beneath. Numerous, moderate numbers, 

 or few round black spots, encircled by a light ring on the gill covers and upper 

 surface of the head, while the upper half, or two-thirds of the body, has numerous 

 X-shaped or even rounded black spots scattered over its surface. Dorsal fin gray, 

 with numerous black white-edged spots, but without any white tip to the fin : 

 frequently black marks upon the adipose dorsal. Usually the upper half of the 

 caudal fin is spotted. At Howietown, where such excellent opportunities exist 

 for trying the effects of various forms of food and watching the results, it has 

 been observed (page 61) that on arriving at the fourth year a general yellow 

 tinge shows itself. On first seeing a pond of these fish which have been fed upon 

 clams, and as they come to the surface in large numbers, when a little food 

 is thrown in, they gi-ve the observer the idea that he is looking at the common 

 brook-trout, and it is not until some have been removed from the water and their 

 comparatively short heads seen, that the illusion is dispelled. In the tanks in 

 which horse-flesh and vegetables are given as food an apparently very different 

 sort comes to the surface, having a bright silvery hue with black spots, and it 

 seems difiicult to realize the fact that this is almost entirely due to change of diet. 

 I have also alluded to (page 61) how these fish when in the parr stage retain 

 their red spots up to the period of eighteen months, or even three years, but that 

 such may likewise be perceived in these trout when intermediate between kelts 

 and fresh run or well-mended fish. Although in some few examples they may 

 be present all the year round. 



Lacepede's species from the lakes of Cumberland and Scotland, having a small 

 head, with white flesh, and externally of a gray colour, is very probably this 

 species. Dr. Knox (Joui'n. Linn. Soc. Dec. 19th, 1854), observes, at first he 

 had thought this a specific form, " although anatomical investigations had not 

 hitherto confirmed it." He remarked that it was in the highest condition from 

 December until March. 



This form of trout agrees with the variety of the sea-trout termed Salmo alhus, 

 in its same short head, preopercle with a very indistinct lower limb, and pointed 

 pectoral fins, but it differs in the inconstant character of the number of coecal 

 appendages. The most positive difference is in the character of its vomerine 

 teeth, possessing as it does a double row along the body of that bone. In early 

 life all fishes of this genus are well provided with vomerine teeth, which are 

 more deciduous in anadromous than in fresh water forms. This would appear 

 to point out that a fresh water existence is more conducive to their retention 

 than living in the sea is, consequently it might be anticipated that were marine 

 forms to take in a permanent fresh water condition of life these teeth would 

 be less deciduous. This in fact is the distinction between the Loch Leven trout 

 and the white sea-trout, and in the sewin we perceive a graduated series 

 (pao-e 59) from the sea to the fresh water form, whereas in this instance all 

 communication between the two has ceased to exist. Unless the example from 

 Howietown which I dissected is an exception, it would seem that change of 

 locality to a smaller piece of water has been coincident with a decrease in 

 the number of the pyloric appendages, coupled with a decided lengthening of 

 the head. 



Habits. — These are similar to what have been remarked in the brook-trout. 

 During the breeding season it has been observed that some adults possess abraded 



