214 Dr. L. Plate on Asellicola digitata. 



Flagellata remain adherent to them without coming in con- 

 tact with the anterior orifice or being sucked out. In the case 

 of such small organisms the nutriment is simplj pumped into 

 the tentacular canal by means of the tentaculet. Their 

 sucking power does not appear to suffice to overpower larger 

 prey, such as small Infusoria, for in such cases our Suctorian 

 adopts another mode of proceeding. It draws in the greater 

 part of the whole tentacle, so that it shows only one fourth or 

 one third of its original length. The tentaculet also entirely 

 disappears, and the tentacle acquires the form of a short 

 tube, the uppermost end of which is somewhat widened, and 

 possesses a much folded and wrinkled wall. By a movement 

 exactly corresponding with that of the tentaculet this upper 

 part of the arm then extends itself a little (by which means 

 the folds disappear) and contracts itself again, in this way 

 effecting in a few moments the complete exhaustion of small 

 organisms, such as Vorticellw, so that the cuticle of the cap- 

 tured animal alone remains attached to the tentacle as an 

 empty vesicle. To get rid of this from the sticky point of 

 the tentacle often gives the Asellicola a good deal of trouble. 

 It proceeds in this way : it extends the free extremity of 

 the tentacle into a small narrow tube, then retracts this again 

 suddenly, and thus endeavours to throw off the vesicle. 



By the mode of feeding above described a peculiar appear- 

 ance is produced which may not unfrequently be observed in 

 our Acineta. Thus we find the lower region of the tentacles 

 densely covered with small rod-like Bacteria, which are 

 attached by one end, but for the rest stand off obliquely 

 upwards and outwards (see fig. 5). This foreign covering 

 ceases in all the tentacles at the same level, nearly corre- 

 sponding to the dimensions which the tentacles acquire when 

 devouring prey of considerable size. Evidently the Bacteria 

 can attach themselves only to the proximal parts of the 

 tentacles, because the distal parts are too often retracted 

 during feeding. 



As regards the position and grouping of the tentacles no 

 regularity prevails in Asellicola digitata. They may shoot 

 forth anywhere upon the upper surface of the body and may 

 also be retracted again quite independently of each other. 

 Not unfrequently we meet with individuals quite destitute of 

 tentacles. The protrusion of the sucking-organs occupies 

 several hours ; it is therefore effected rather slowly. During 

 reproduction they generally disappear only in the immediate 

 vicinity of the aperture for the exit of the swarm-offshoots. 

 But if the animal is compelled to quit its previous dwelling- 

 place by the change of skin of the gill-plate, it previously 



