ACTINIA AND OTHER A0T1N0IB POLYPS. 35 



animal so touched, torpor and speedy death. Since the discov- 

 ery of these cnidoe (lasso-cells) the fatal power has been sup- 

 posed to be lodged in them. Baker, a century ago, in speak- 

 ing of the Hydra, suggested that " there must be something 

 eminently poisonous in its grasp ; " and this suspicion received 

 confirmation from the circumstance that the HJntomostraca 

 which are enveloped in a shelly covering frequently escape un- 

 hurt after having been seized. The stinging power possessed 

 by many Medusae, which is sufficiently intense to be formida- 

 able even to man, has been reasonably attributed to the same 

 organs, which the microscope shows to be accumulated by mil- 

 lions in their tissues. 



" Though I cannot reduce this presumption to actual cer- 

 tainty, I have made some experiments, which leave no reason- 

 able doubt on the subject. First — I have proved that the ecthor- 

 ceum (tubular thread of the lasso-cell) when shot out, has the 

 power of penetrating, and does actually penetrate, the tissues 

 of even higher animals. Several years ago, I was examining 

 one of the purple acontia of Adamsia palliata ; no pressure 

 had been used, but a considerable number of cnidoe had been 

 spontaneously dislodged. It happened that I had just before 

 been looking at the sucker-foot of an Asterina, which remained 

 still attached to the glass of the aquatic box, by means of its 

 terminal disk. The cilia of the acontium had, in their rowing 

 action, brought it into contact with the sucker, round which it 

 then continued slowly to revolve. The result I presently dis- 

 covered to be, that a considerable number of the cnidoe had 

 shot their ecihorcea into the flesh of the sucking disk of the 

 Echinoderm, and were seen sticking all round its edge, the 

 wires (lassos) being embedded in its substance even up to the 

 very capsules, like so many pins stuck around a toilet pin- 

 cushion. 



