Mr. E. W. IT. Holdsworth on Digestive Power in the Actiniae. 277 



Some of these particles, when submitted to a magnifying power 

 of 450 diameters, occasionally exhibit definite structure; but 

 usually they are all homogeneous in their composition, and show 

 no trace of muscular stria or distinct fibre. 



In the first two cases the remains are enveloped in a tenacious 

 glairy mucus, proving them to have been ejected from the po- 

 lype ; in the third condition this evidence is not so decided. 

 How r ever, in order to avoid any possibility of mistake as to the 

 origin of these particles, separate Actinia were placed in small 

 glass vases, each containing only clean water and a stone bear- 

 ing the single polype : the results of feeding them under these 

 circumstances agreed with what were before observed; and when 

 the meat was returned in the first condition, it was found lying 

 on the stone or bottom of the glass ; when in the second form, 

 it was most frequently floating at the surface of the water ; and 

 if in the third and disintegrated state, it was always in that po- 

 sition, and immediately over the polype, unless intercepted and 

 entangled in the mucous epidermis, as sometimes happens in 

 the case of Act. mesembryanthemum. 



Now let me ask, can we entirely account for these effects by 

 the simple act of squeezing, or any other mechanical operation 

 that can go on within the soft body of the polype ? It appears 

 to me impossible. But strong as the evidence is of the action 

 of some solvent when only small disintegrated particles are 

 returned, my latest experiments are still more conclusive of its 

 existence. Of six Actinia', that were fed from the same bit of 

 meat, two threw up a few very small particles ; the others, after 

 an interval of more than a week, returned absolutely nothing 

 that could be detected with the aid of a lens. These four 

 polypes are two varieties of Sagartia troglodytes, a S. nivea 

 and a S. viduata — all of them voracious species ; the others are 

 S. venusta and Act. mesembryanthemum. 



No mechanical power will account for these results ; and for 

 their explanation I can only have recourse to the alternative, 

 chemical agency, which Mr. Lewes selects as "the specific cha- 

 racteristic of the digestive process," but whose existence he denies 

 in the Actinia, Of the origin and nature of the solvent I can 

 say nothing ; but I would direct attention to the glairy mucus 

 so abundantly produced in the stomach of the polype when its 

 surface is irritated by the presence of food. Possibly this may 

 act only in a preparatory manner ; but that it is concerned in the 

 alimentary process there can be no question, as it is specially 

 called forth under the excitement of feeding. This mucus ap- 

 pears to be a product of the stomach, since it is found coating 

 the food before it has descended into the cavity of the body, as 

 may be proved by giving a polype a piece of meat too large to 



