MY review1 of McAtee's work2 on the effectiveness of so-called ‘protective’ adaptations in animals was written to direct the attention of naturalists to a unique accumulation of facts bearing on a problem which it has become customary to regard as solved in accordance with certain preconceived dogmas. That the paper in question does deserve this attention is proved by the replies and comments aroused by my review. Although the review contained only a brief and almost verbatim representation of the chief facts and conclusions reached by McAtee and not of my own views (which, I admit, are close to his), the critics did me the honour of addressing their replies to me, and I feel bound to answer them, while I hope that McAtee himself will not fail to express his views on the criticisms offered.