SALMONID^E. 99 



rounded, and had no distinct lower limb. The maxilla was much feebler than 

 seen in some other local races of brook-trout, which was remarkably the case on 

 comparing it with a beautiful Yorkshire variety sent me by Mr. G. Brooks, f.l.s. ; 

 but even among the Yorkshire specimens I found great differences to exist. 

 These Cardiganshire fish in the Tivy are found to 4 lb. or 5 lb. weight, but rarely 

 if ever take a fly when so large, but are to be caught by means of a minnow. 

 Small ones removed to a pond attain in about 3 years to 31b. or 3^ lb. in size, 

 their flesh is pinkish, and their flavour said to be excellent. Out of 8 examples, 

 6 had no red spots, one had them along the lateral-line : and the last had them 

 both on the lateral-line and in one or two rows below it.* 



If a trout, normally belonging to a small race, as 8. Gomubiensis, is transferred 

 to a lake or reservoir, as in the one near Penzance, where food is plentiful, it 

 attains a size to which it never reaches in its ancestral stream, showing capacity 

 for growth to be inherent, and called into action by luxuriant living. In Scotland 

 the largest examples are in lochs ; so also in Wales and Ireland, although 

 occasionally a large one may be found in a sluggish stream, especially if such 

 passes over a rich soil. Should food be plentiful, a brook-trout may attain to many 

 pounds in weight in suitable localities — in fact" to as large a size as the great 

 lake-trout, which I hold to be merely a form of 8. fario which indulges in 

 luxurious living, or cannibal propensities. 



Variety e. — Salmo estuarius, Plate OIX, fig. 3. 



Salmo estuarius, Knox, Zoologist, 1855, xiii, p. 4662. 



Salmo gallivensis, Giinther, Catal. vi, p. 88 ; Houghton, Brit. Freshwater 

 Fishes, p. 105, c. fig. 



The most characteristic peculiarity of this form is said to be found in the 

 small size of the coecal appendages : also that it is at once recognized from Salmo 

 trutta by the excessive shortness of the tubes on the lateral-line. Four examples 

 were recorded and four more passing into the brook-trout, termed hybrids. It is 

 similarly coloured to freshwater forms. Knox's example had sixty vertebrae, 

 similar to the number present in the British Museum specimen, and the name he 

 gave well denotes the chief characteristic of this variety. The example figured 

 is 19 inches long, and came from Waterford. Mr. J. Harvie-Brown took in June, 

 1882, from a sea-pool or fish-pool at the mouth of the river, freshwater at low tide, 

 salt or brackish at high- water, brown-river trout, periodically visiting the brackish 

 localities, and taking on a silvery sheen of scales, much as he found them in 

 North Uist. They are said to lose condition about spawning time, then disappear 

 but not to ascend streams to breed. Couch alludes to Knox's estuary trout and 

 observes upon its being a fish which has gone to the sea, and that he had received 

 examples migrating seawards in May towards the deep. 



Variety /. — Salmo stomachicus. 



The Qillaroo, Barrington, Phil. Trans. Royal Soc. 1774, lxiv, p. 116 ; Watson, 

 1. c. p. 121 ; Hunter, 1. c. p. 210 ; Sowerby, Brit. Misc. t. lxi ; Yarrell, Brit. Fish, 

 (ed. 3) i, p. 283 ; Thompson, Nat. Hist. Ireland, iv, p. 154 : Couch, Fish. Brit. 

 Isles, iv, p. 240, pi. ccix. 



Salmo stomachicus, Giinther, Catal. vi, p. 95 : Houghton, Brit. F. W. Fishes, 

 p. 125, c. fig. 



This has been considered distinct, due to the abnormal thickness of the middle 

 coat of its stomach, otherwise, observes Mr. Barrington, there are no exterior 

 marks by which the species can be distinguished from the common trout. 

 Pennant asserted that the increased thickness of the stomach proceeds from the 

 superior quantity of shell-fish which it finds in the waters it inhabits, and which 

 may call more frequently for the use of its comminuting powers than is requisite 



* I intend depositing all these forms, along with my British collection of fish, in the South 

 Kensington Mnseum. 



7 * 



