288 Dr. G. C. Wallich on an undescribed 



bodies, neither the outer layer of sarcode, nor the more viscid 

 mass within, is endowed with a more advanced degree of 

 development at one point than at another. And, in addition to 

 this, the creature possesses the power of moving with equal 

 facility in every direction, by means of pseudopodia projected 

 indiscriminately from any portion of its surface. 



In the variety under notice (see Plate VIII.) this is not the case, 

 inasmuch as one portion of the ectosarc exhibits a structure 

 differing permanently from the remainder — being densely studded 

 with minute papillae which, in the quiescent state of the creature, 

 are of nearly uniform aspect and size, and cause the surface 

 upon which they occur to resemble the villous structure of 

 mucous membrane in outward appearance. When the animal 

 moves, these papillae or villi vary in length, and now and then 

 several coalesce so as to form processes more nearly approaching 

 the ordinary pseudopodial character, although still of minute 

 proportions. The villous patch, which occupies probably from 

 ^th to y^th of the entire superficies, appears frequently to be 

 employed as a prehensile organ, the creature being enabled 

 through its agency to secure for itself a continuous point d'appui 

 from which the rest of the body is pushed or flows onwards, 

 almost invariably in an opposite direction to that in which the 

 villous patch is itself situated. The true pseudopodia would 

 seem never to be projected from this area; but should a retro- 

 grade movement be about to take place, they are either thrown 

 out from the adjacent portion of the ectosarc, or the main mass 

 of the organism flows altogether in a backward course, the villous 

 patch remaining fixed until it once more assumes its position at 

 the posterior part of the advancing mass. 



So powerful is the prehensile power referred to, that some 

 of the papillae at times become stretched beyond their endurance 

 and are torn asunder ; minute shreds being left adherent to the 

 foreign bodies in the neighbourhood. Should the animal be 

 subjected to pressure between the slide and glass cover, the 

 papilla? may occasionally be seen to adhere to the polished sur- 

 faces, some relaxing their hold and taking up a position in 

 advance, whilst those described as being stretched till they 

 detach or break asunder are, in turn, moved onwards until 

 they once more secure an attachment for themselves. 



On the other hand, the pseudopodial processes and the rest of 

 the ectosarc generally seem to exercise no prehensile power. In 

 the one case the marginal layer is broken up into a delicate 

 villous coat, the hyaline transparency of which is destroyed and 

 replaced by a pale cream-coloured opacity ; in the other it is 

 perfectly hyaline, clearly defined, and unbroken. I have only 

 in a very few instances been enabled to trace an influx of granu- 



