fly-shaker is maintained, the occasional use of which in winter and frequent use in summer and the active purposeful switching of tail, twitching of ears and jerking of head have their limited value. Here there is ample room for diverse opinion and the opponent will ask with some degree of force how we know that there is no more benefit to the cow from its fly-shaker than a mild degree of comfort, and may assert that the possession and use of it may have survival-value by its defence against deadly parasites. We do not know, nor does he, but it would seem that except for the tsetse fly in Africa the plague of flies does little to an ungulate beyond irritating its brain, and if he had no fly-shaker, he would still be able to reach a considerable distance with his tail, ears and head over the irritated regions. The question of survival indeed resolves itself into the vigour and energy of his integrating brain. To this view of the function and origin of the panniculus carnosus the busy systematist and student of genetics may refuse to listen, and pass to the order of the day, but I submit that in stating a position it is useful to put forward a crude example in which the issue is plain, and which subsumes an immense number of smaller and more subtle cases, and in a region where the most hardy rebel will not dispute altogether the sway of _personal_ selection. It is a question here of the manner in which, speaking in metaphor, the early ungulate first set about making his eolithic or palæolithic weapons and fashioned them into what we see to-day. “Forged by the incident of use” and habit meets the story of the fly-shaker far better than some mutation arising in far back ages or some dominant variation, or “useful variation within the germ.” At any rate Lamarck finds the raw material to hand, and there are supplied adequate noci-cipient stimuli with response, in regions where these are most active under the dominating action of the brain. Other Muscles.