322 APPENDIX. 



Bomare and M. Bosc have unsuccessfully repeated the experiments 

 of Reaumur and Bonnet, both on the Earthworms and on the Naides. 

 Reaumur, the only one who says that he had seen the head repro- 

 duced, makes merely a simple assertion of the fact ; and Bonnet 

 reduces this almost to nothing, impliedly and directly, when he in- 

 forms us that all the worms died before the reproduction of the front 

 part was completed. He was moi'e fortunate with the Naides. For 

 a long time Duges believed the assertion of Reaumur to be without 

 any proof. In his experiments, a worm, when cut into two portions, 

 remade readily an anus in the anterior portion, for the healing of the 

 wound sufficed for this ; but the posterior portion, although pre- 

 served alive for four or five months, showed no appearances of any 

 new growth in front. It died at length from inanition, remaining 

 on the surface of the moist earth, in which it had buried only its 

 hhider extremity. We can easily imagine how difficult it must be 

 for the nutritive function to reproduce a part in which are seated not 

 only a ganglion peculiar in its position, but a mouth also, stomach, 

 moniliform vessels, and organs of generation. In the posterior part, 

 on the contrary, reproduction has nothing in it unnatural. The 

 growth which goes on before maturity adds to the body ring after 

 ring in succession, each acquiring its new ganglion, as we can easily 

 observe in the Naides and in the Myriapods : — and so are lost parts 

 replaced. 



These reflections induced Duges to simplify the experiment. Thus, 

 considering that the organs are situated in the most inflated part of 

 the Lumbricus, he cut away only the first four or eight rings, satis- 

 fying himself that a part of the oesophagus and of the nervous system, 

 the cephalic ganglion at least, had been removed in the section. At 

 the end of ten days (it was in the month of June, when the ther- 

 mometer was about 18° Reaum.), if only four rings had been cut off, 

 and after two or three times as many, if seven or eight rings had 

 been removed, Duges observed a conical reddish obtuse mamilla 

 project in front. In eight or ten days more this growth had become 

 more pointed, very contractile, red and moist, and the extirpated 

 rings could be perfectly recognized, — the anterior lip and the mouth, 

 still very small, but of the normal shape. Then the worm began to 

 burrow in the earth, and crawled with the head foremost ; and then 

 the intestine began to be filled with the earth which the Lmnbrici 

 swallow for food. Gradually this new portion acquired the size of 

 that which it replaced. These experiments made on Lumbricus 

 trapezoides, probably identical with our L. ten'estris, leave no doubt 

 that a limited portion of the front can be reproduced : but it still 

 remains doubtful whether, when a worm is cut in two halves, each 

 half will ever become a perfect worm ; for Duges found that when 

 the section was considerable, the part soon died. 



Duges does not doubt the correctness of the conclusions drawn 

 from the experiments of Bonnet and IMiiller on the Naides. — Ann. 

 des Sc. nat. xv. pp. 316-319. 



Bearing on the question, it may be mentioned that the Eunice 

 sanffuinea, which has a highly developed cerebral organization, can 



