1196 Recent Literature. [ December, 
active ambulacral rows to touch the floor of the tank, and when 
they have established their hold they assist in increasing the tilt; 
then the next feet in the series lay hold, and so on till the globe 
slowly but steadily rises upon its equator.” Finally it lets itself 
3j JES 
Fic, 10.—Echinus beginning to right itself. 
down very slowly and carefully, the feet on one side preventing 
its too rapid descent (Fig. 11). 
Experiments on stimulation were made with the result of 
vous plexus.” Accordingly the author and Professor Ewarts 
went to work to see if they could obtain any microscopical evi- 
Fic. 11.—Echinus nearly righted. 
dence of such a plexus. This they succeeded in doing, and 
afterwards found that Professor Loven had already briefly men- 
tioned such a plexus as having been observed by him. ‘The 
_* plexus consists of cells and fibers closely distributed all over the 
_ Surface of the shell, immediately under the epidermal layer of 
cells (Figs. 12, 13), and it sends fibers al! the way up the feet, 
nes and pedicellariz. This important discovery led to i 
er experiments on sections. It appears that single rays, when 
of from the body, crawl as Se ad in as Meanie a direc- 
