0)1 Reproduction of Lost Parts and Abnormality. 365 



deserve. At least, few will now give tliem the high place 

 they once held in biology. Science seems to me to lead to 

 the very edge of an explanation, but I doubt if it can ever 

 go farther. Dareste's object is to show how abnormalities 

 can be artificially produced, with the view, evidently, of 

 suggesting that the cause being known might lead to pre- 

 vention if not to cure. While both authors use the term 

 " abnormal," both equally question its appropriateness, and 

 desire to bring all the phenomena to which it points into 

 natural lines. 



I have associated the reproduction of lost parts with the 

 occurrence of abnormalities, because both point to char- 

 acteristic features of the one life, in conditions unfavour- 

 able to its natural growth and expression, and also because 

 the injuries which make reproduction necessary, may, and 

 often do, lead to abnormal forms. (This was illustrated by 

 the exhibition of the pastern and coffin bones of the horse in 

 an abnormal condition.) 



The phenomena of reproduction of lost parts are met with 

 in all the classes, both of invertebrate and vertebrate animals, 

 and point to phases of success in the effort to overcome 

 hindrances to living, not, perhaps, sufficiently appreciated. 

 To indicate the wide range within which instances of repro- 

 duction of parts occurs, I need only mention that examples 

 under Hydridm, Holotliuridm, Asteridm, and Canceridce, among 

 invertebrates, have come under my own observation. As to 

 the last named, there is an exceedingly able and interesting 

 paper on its occurrence among common crabs, by Harry D. 

 Goodsir (printed in volume ii. of " Anatomical Memoirs of J. 

 Goodsir," edited by Turner and Lonsdale). Goodsir shows 

 that if the phalange of the leg of the common crab be injured, 

 the animal at once throws off the remaining parts of the 

 limb close to the body. By which act, as he proves, it both 

 saves the loss of blood and lays bare the organ which is to 

 reproduce the lost limb. 



As to fishes, Gunther has pointed out (" Study of Fishes," 

 p. 188, 1880) that the power of reproduction of lost parts in 

 the Teleostei is limited to the delicate terminations of their 

 fin-rays, and the various tegumentary filaments with which 



