ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 53 



more complex Vertebrates. Two genera of Ctenophora, Beroe and 

 Chiaja, have lately afforded Dr. C. F. W. Krukenberg an opportunity 

 of further studying the difficult problem here in question. The effects 

 of various mechanical injuries and poisons on these two gelatinous 

 organisms were carefully noted. Atropin, helleborein, digatalin, and 

 camphor exert little influence on either of them. Coniin, nicotin, 

 physostigmin, quinine, &c., yield results which are not satisfactory. 

 But most remarkable contrasts were discovered by using strychnine 

 and curare. 



A Beroe cut across so that six rows of combs were completely 

 severed, two being left uninjured, was placed with one half in a 

 solution of strychnine ; the other moiety floated in pure sea-water, a 

 stream of which also moistened the undivided isthmus crossing the 

 edges of the contiguous vessels that contained these different fluids. 

 The aboral* half, immediately exposed to the poison, showed the 

 same phenomena as an unmutilated Beroe similarly treated ; the combs 

 ceased to act, contractions of the body-wall ensued, afterwards all 

 movements stopped, and finally death occurred. After a pause of 

 about ten minutes, the oral halves of the two uninjured meridians 

 resumed the play of their combs, at first irregularly, subsequently 

 with due regularity and persistence. The severed oral meridians 

 were not affected. The combs of the isthmus, too near the poison, 

 were brought to stillness. When the experiment was reversed, so that 

 the oral half was immersed in the poisonous liquid, like changes were 

 seen, except that resumption of their activity by the aboral halves of 

 the rows of combs was regular from the first ; the oral combs were at 

 once deprived of motion. 



' Curare affects Beroe in a very singular manner. The combs not 

 only come to rest, but are sunk in recesses of the meridians formed 

 by the rising up on either side of the adjacent contractile wall of the 

 body. 



In Chiaja, on the other hand, we quite miss this curious retro- 

 cession. Curare, as well as strychnine, has little effect on this 

 organism. Fragments of Chiaja show no pause or irregularity in the 

 movements of their combs. 



The formal differences between Beroe and Chiaja, which meet the 

 eye of the comparative anatomist, do not help us in trying to account 

 for such very notable constitutional pecularities. The much softer 

 consistence of the general textures of Chiaja seems to furnish a more 

 promising datum. There is little doubt that each locomotive comb 

 possesses its own " automatic " centre. We must also assume separate 

 centres for the meridional musculature, and these again are governed, 

 inhibitorily or otherwise, by the conspicuous ganglion of the aboral 

 region. 



Dr. Krukenberg sets before us, in an ingenious diagram, what he 

 believes to be the mutual relations of the Beroe' s principal nervous 

 centres. He expressly guards himself, however, against exaggerating 

 the value of the sagacious hypothesis which he suggests, and concludes 

 by reiterating his strong conviction that the essential complexity of 

 * Read ahoralen for oralen in text, p. 8, line 14. 



