ascertained the truth by observation.  Mr Shaw was, therefore, entitled to proceed as if the matter were solely in his own hands; and he makes no mention either of the “vain imaginations” of Dr Knox, the more careful compilation of Mr Yarrell, or the still closer, but by no means approximate calculations of Richard Parnell, M.D.  In this he has acted wisely, seeing that his own essay professes to be simply a statement of facts, and not an historical exposition of the progress of error.

It would, indeed, have been singular if two species, in many respects so closely allied in their general structure any economy, had been found to differ very materially in any essential point.  It now appears, however, that Mr Shaw’s original discovery of the slow growth of salmon fry in fresh water, applies equally to sea trout; and, indeed, his observations on the latter are valuable not only in themselves, but as confirmatory of his remarks upon the former species.  The same principle has been found to regulate the growth and migrations of both, and Mr Shaw’s two contributions thus mutually strengthen and support each other.

The sea trout is well known to anglers as one of the liveliest of all the fishes subject to his lure.  Two species are supposed by naturalists to haunt our rivers—­Salmo eriox, the bull trout of the Tweed, comparatively rare on the western and northern coasts of Scotland, and Salmo trutta, commonly called the sea or white trout, but, like the other species, also known under a variety of provincial names, somewhat vaguely applied.  In its various and progressive stages, it passes under the names of fry, smolt, orange-fin, phinock, herling, whitling, sea-trout, and salmon-trout.  It is likewise the “Fordwich trout” of Izaak Walton, described by that poetical old piscator as “rare good meat.”  As an article of diet it indeed ranks next to the salmon, and is much superior in that respect to its near relation, S. eriox.  It is taken in the more seaward pools of our northern rivers, sometimes in several hundreds at a single haul; and vast quantities, after being boiled, and hermetically sealed in tin cases, are extensively consumed both in our home and foreign markets.  But, notwithstanding its great commercial value, naturalists have failed to present us with any accurate account of its consecutive history from the ovum to the adult state.  This desideratum we are now enabled to supply through Mr Shaw.

On the 1st of November 1839, this ingenious observer perceived a pair of sea-trouts engaged together in depositing their spawn among the gravel of one of the tributaries of the river Nith, and being unprovided at the moment with any apparatus for their capture, he had recourse to his fowling-piece.  Watching the moment when they lay parallel to each other, he fired across the heads of the devoted pair, and immediately secured them both, although, as it afterwards appeared, rather by the influence of concussion than the more