FRESH- WATER TROUT— LOOHLEVENS DESCRIBED. 223 



alternately to tlie right and left. (3) In & female 10'9 inches long, 2 at hind, edge 

 of head of bone, 2 in a line at the commencement of the hody, and 8 as in the 

 last specimen, hut more distinctly in pairs. (4) In a female 13'5 inches long, 2 

 at hind edge of head of vomer, then 4 in a single row, next a pair turning one to 

 either side, and lastly, 4 more single ones. (5) In a male 14 inches long, 2 teeth 

 at hind edge of body of vomer, 9 in a single row along the body of that bone ; of 

 these the two centre ones form, a pair. (6) In & female 19"2 inches long, 4 teeth 

 at hind edge of body of the vomer, 12 along the body, among which are three 

 pairs. (7) In a, female 23 inches long, 3 at hind edge of body of vomer, 8 along 

 its body in a' single row, some turning one way and some another. The fore- 

 going would seem to prove that it is by no means an invariable rule that all the 

 teeth along the body of the vomer are in a single row, in fact they are similar to 

 what is seen in trout in many Scotch and Welsh lochs. 



Fins. — These vary in the Lochleven as well as in other forms of trout, which 

 is due to the same causes. The pectoral may be more pointed in the young than is 

 generally seen in the brook trout, but similar to the white sea trout, and reaches 

 to about half-way to the base of the ventral, ■which 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. The caudal fin has been stated to be much longer* than seen in the 

 burn trout and its posterior end to be truncated and pointed at both its upper and 

 lower angles. But it will be seen on referring to fig. 50 that such characters have 

 been given because the observers have examined young examples, the fin becoming 

 convex posteriorly with age (see no. 14 at 22 inches in length). 



The statement that the pectoral fin is pointed is partially correct in small 

 specimens, as it also is in small brook-trout, but in old and well-preserved 

 examples it is similar to what is found in other races of fresh- water trout, as may 

 be seen in figure 42, p. 187. 



Scales. — There are 13 to 15 rows in an oblique line running from behind the 

 base of the adipose dorsal fin downwards and forwards to the lateral-line. Coecal 

 appendages : Richardson found 73, Parnell 80, Griinther 49 to 90, due either to 

 several becoming confluent into one stem, or one subdividing into several, but 

 anyhow demonstrating inconstancy in numbers. The number of these appendages 

 are exceedingly varied, and from the time Parnell first ascertained that these trout 

 often possess a larger number than are usual in brook trout, until the present day 

 this has been held conclusive evidence as to their specific difference from other 

 races. Many who would admit that variations in external colour or that of the 

 flesh, or even alterations in form, may be dependent on local surroundings, will 

 be slow to believe that structural differences are not of much greater value. 

 Here we must first inquire whether the number of these pyloric caeca are constant 

 in the Lochleven race of trout, whether they ever vary in the brook trout, and, 

 lastly, if any facts can be produced proving them to be inconstant ? 



Having thus shown that these appendages in the Lochleven trout have been 

 recorded as between 49 and 90,t while in other non-migratory fresh-water forms 

 they have been found to be between 27 and 69 (see p. 188 ante), I propose 



* As to tlie rays of the caudal fin being longer than is seen in the brook trout, I have 

 been unable to find that such is the case, either in Howietoun specimens, those from Lochleven, 

 or those in the British Museum, as they seem to be absolutely identical in the two forms. In 

 the skeleton of a female 20 inches long, I find the middle caudal ray is 2-1 inches in length, and 

 the longest outer ray 2-9 inches ; but were Dr. Giinther's figures to be applicable to these fishes, 

 the outer ray should be 4'1 inches in length ; but such proportions 1 have never seen in the 

 thousands of these fish I have observed at Howietoun or elsewhere, not omitting those in the 

 British Museum. Specimens having the angles of this fin pointed would appear to be young fish, 

 often males, kept, as at Howietoun, where they are hot disturbed ; but in the old fishes this fin is 

 invariably rounded at its posterior extremity. The statements in the British Museum catalogue 

 alluded to are that — " In specimens 13 inches long, the middle caudal rays are not quite half as 

 long as the outer ones, and in older ones they are half as long " (Gunther.) Also that in a 

 specimen 13J inches long, the middle caudal ray was 1 inch in length and the outer or longest 

 one If 1 



t Among the local Lochleven forms (see p. 188 ante) Parnell found 60 to 80 Cffica, Sir J. 

 Eichardson 73, and Gunther from 49 to 90 ; but although the last author in his description of the 

 species says, " Ceeoal pylori normally 60 to 80," he instances seven females in the British Museum 



