six years these fish have now been in our harbour, have seen or heard of the young fry being in these streams, but we have not. Such a thing as a sea-trout spawning in salt water is unknown, and it will be very surprising if our S. trutta are found so to do. There is thus a mystery as to the habits and movements of our S. trutta, sufficient almost to throw doubt on their identity. Still we are in this position—we have a trout got only in the salt water, specifically differing from the common trout of our streams, and agreeing in its distinguishing marks with S. trutta. It is caught in the salt water varying in weight from 1 lb. to 18 lbs., and is often found in spawning condition in the beginning of our summer. Hitherto no well verified example has been taken in any of our streams. Much remains, therefore, to be discovered of the habits in our waters of this fish, which I do not doubt, after the examinations I have made, is the real Salmo trutta. The sea-trout of Otago were brought from Tasmania as ova by Mr. Clifford, 137 young fish being turned into Shag river in 1871, at which time also I understand a few more were put into the Water of Leith, at Duncan's mill. Distinguishing Marks. These marks, I will endeavour, in closing this paper, to summarize briefly; and in doing so I may say that I give them partly from my own observations, and partly as I find them given by the best authorities. They refer only to adult fish. Of the S. quinnat and S. paucidens, I cannot venture to lay down from my own experience rules for their identification from other salmon of the same genus, the Oncorynchus, as my knowledge of these fish is as yet very limited. It would require years of residence and study in California or Columbia to acquire such knowledge correctly, and as yet I have not been able to find any author who gives a full and accurate description of these fish. At the same time there is no difficulty in recognizing the difference between these and the Salmo salar. They belong to a different genus, the Oncorynchus, where the anal rays exceed 14, while in the S. salar these are always less, being rarely more than 10.* Mr. Lord describes the margin of the operculum as having spinous projections which give it a serrated form. But of the S. salar I may say that it may be most readily distinguished from the other species (S. trutta and S. fario) of the genus Salmo, by its strong and uniform coating of burnished silvery scales, 12 in transverse row from adipose to lateral line; its fine sharp and clean-cut head; its arched back and deep belly, its taper and cylindrical shape towards the tail, its large square tail, sometimes emarginate; by the fewness, and x-shape of its