390- MKS. L. J. VELFA' — CONTniTJUlTOX TO TDE 



This appeared to me, from a study of many individuals, to be- 

 ouly the case wheu the animal is sluggish or creeping very 

 quietly ; at such a time the contour is certainly perfectly even, 

 and the pseudopodia are as described, showing the hyaline border 

 very clearly (PI. 37. fig. 18). Under circumstaoces equally 

 norma], but inducing greater activity, as when a portion is con- 

 stricted off naturally, or the animal is getting rid of a large solid 

 or rigid body, the contour frequently becomes temporarily quite 

 ragged, and whip-like pseudopodia of exceeding fineness are 

 shot out with great suddenness and velocity, extending to a con- 

 siderable length (p. 391). Pseudopodia of this kind are ex- 

 ceedingly attenuated and acute, and are, for a great part of their 

 length from the tip inwards, perfectly hyaline, appearing to bo 

 actual prolongations of the hyaliie border; they often, but by 

 no means always, radiate outwards, and very frequently anas- 

 tomose, the connecting bridge between two pseudopodia being 

 sometimes hyaline (p. 391, A), but more often consisting of 

 fine strands of granular protoplasm (p. 391, B). They are never 

 rigid, and often fall into the most graceful curves. When one 

 of these fine pseudopodia is in course of being retracted, a very 

 curious feature is observable, viz., a peculiar wrinkling of the 

 granular part of the protoplasm, as if it were a soft coating to an 

 elastic core (p. 891, C), yet no such actual distinction can be 

 microscopically detected, although the withdrawal of a pseudo- 

 podium is a far slower process than its extension. 



This observation would appear somewhat to vitiate the 

 classification of Rhizopoda recently proposed by Professor G. S. 

 A-Vest, which is founded chiefly on the nature of the pseudnpodia, 

 and in which it is stated that those of the order Amoebcea, to 

 which Pelomyxa is assigned, are " rarely attenuated and acute, 

 sometimes branched, but never reticulate." It appears to the 

 writer that pseudopodia in general are too transient characters 

 on which to base a classification, and that those of Pelomyxa 

 in particular do not agree with the description prop)osed by 

 Prof. West in his interesting paper. 



Prof. West's suggestion that the " characters of the nucleus " 

 in E;hizopods are " of much less imjDortance iu these animals 

 than might at first be imagined " was borne out as far as my 

 experience went. In the many experiments made by me witli 

 living Pelomyxcd in nutrient fluids, when they very commonly 

 divided, the nuclei were always examined for any characteristic 



