DURING last year I noticed that Harvestmen (Opiliones) do not regenerate lost legs when they moult, and this summer I have determined that they do not regenerate pedipalpi either. It seemed possible that this surprising deviation from a general character of the Arachnida might be related to the contrast between the length of the limbs and the shortness of the cephalothorax, within which it would be impossible to develop a leg long enough to be useful when exposed by ecdysis, and that, if this were so, the same peculiarity might be shown by spiders with very long legs. A specimen of the spider Pholcus phalangioides, sent to me by Dr. W. S. Bristowe, has just cast its skin and shows no trace of a new leg to replace one which I removed four weeks ago.