80 Dr. Reid on the Development of the Medusae. 



this experiment by placing those detached in separate vessels, 

 and almost always successfully, when care was taken to disturb 

 them as little as possible for three or four days, or longer. A 

 considerable number of larvse are adhering to the surface of the 

 vessels in which the stones are kept *. 



I made several experiments upon the reparative powers of the 

 larvse. In several the upper half of the body was cut off, and 

 after three or four days its lower or cut end had closed in, and 

 by the sixth day it had attached itself to the surface of the ves- 

 sel, and shortly assumed all the appearances of an entire larva, 

 sending out stolons and forming buds. Fig. 12 is a representa- 

 tion of the upper half of a larva eight days after it had been cut 

 off. New tentacula, and a new mouth also, after several days 

 presented themselves on the upper or cut end of the lower half. 

 Several were divided longitudinally through their entire length, 

 and when means were not taken to keep the cut edges apart 

 they soon adhered again, and no traces of their division remained. 

 In one divided longitudinally the two portions were kept apart, 

 and in each the cut edges approximated and adhered, and two 

 separate animals were thus produced from one. 



The larvse are voracious, and readily seize and swallow uni- 

 valve or bivalve molluscans, or a crustacean, as large or even 

 larger than their own bodies before they are stretched out, and 

 after retaining them in the stomach, generally for about twenty- 

 four hours in summer and nearly twice as long in winter, they 

 reject them through the mouth. They also not unfrequently 

 swallow one of their neighbours, and its sojourn in the stomach 

 for some time terminates in its digestion and destruction. When 

 they seize a univalve moUuscan too large to be swallowed, they 

 retain it firmly embraced in their tentacula, and insert their elon- 

 gated mouth into the interior of the shell ; and in like manner 

 they keep dead articulate animals, or molluscans without shells, 

 too large to be swallowed, in their tentacula for more than a day, 

 and probably extract nourishment from them by acting on their 

 textures by their extensible lips. 



The larvse of the first colony, obtained in September 1845, did 

 not split transversely into young Medusie in the spring of 1846, as 

 I expected them to do, but continued to produce stolons and buds 

 abundantly. A great number of them had then attained a large 

 size, and many of them presented on their outer surface transverse 

 rugse, and four pretty deep equidistant vertical grooves, as repre- 

 sented in fig. 13, but none of them presented the appearances now 



* According to Sars, "si on detaclie violemment ces polypes, il n'y a 

 qu'un petit nombre qui peut se fixer de nouveau, et alors ils n'adherent pas 

 si fortement qu'a Tordinaire ; la plupart restent libres au fond du verre." — ■ 

 Opus cit. p. 339. 



