228 JELLY-FISH, STAR-FISH, AND SEA-URCHINS, 



being thus no longer responsive to central stimula- 

 tion. It remains, liowever, for a long time responsive 

 to stimulation of the neuro-muscular sheet ; indeed, 

 the strength of the alcohol solution must be very 

 considerable before loss of muscular irritability 

 supervenes. It may thus be made to do so, how- 

 ever; and on then transferring the animal to normal 

 water, recovery begins in from three minutes to a 

 quarter of an hour. The first contractions are very 

 feeble, with long intervals of repose ; but gradually 

 the animal returns to its normal state. 



The above remarks apply also to Tiaropsis. In 

 Tiaropsis indicans the manubrium recovers in normal 

 water sooner than the nectocalyx. Both in Sarsia and 

 Tiaropsis the manubrium and tentacles are retracted 

 while exposed to alcohol, and, after transference to 

 normal sea-water, the animals float on the surface, 

 presumably in consequence of their having imbibed 

 some of the spirit. The period during which flota- 

 tion lasts depends, {a) on the strength of the alcohol 

 solution used, and (6) on the time of exposure to its 

 influence. It may last for an hour or more ; but in 

 no case is recovery complete till some time after the 

 flotation ceases. 



11. Curare. — Curare had already been tried npon 

 Medus?e, and was stated to have produced no eflfects ; 

 it is therefore especially desirable that I should 

 first of all describe the method of exhibiting it 

 which I employed. 



Having placed the medusa to be examined in a 

 flat-shaped beaker, I filled the latter to overflowing 

 with sea-water. 1 next placed the beaker in a 



