RECENT MEMOIRS ON FRESHWATER RHIZOPODA. 361 



for some time under observation, and after having recovered 

 the shock of removal from the gathering to the slide, and of 

 putting on the covering glass. 



When the pseudopodia carry granules, these are generally 

 of greater diameter than the pseudopodia themselves, and 

 hence cause little swellings ; when these occur, several in 

 succession, a submoniliform or somewhat torulose aspect is 

 (temporarily) imparted to the pseudopodium ; sometimes in 

 some forms little fusiform thickenings of the pseudopodium 

 itself may occur, which may slowly travel up and down. 



H ertwig and Lesser divide the Skeletophora into two sub- 

 groups, their distinctions based on whether the skeleton 

 consists of numerous loose pieces, this subgroup they desig- 

 nate Chalarothoraca — or of a solid and connected shell, 

 which subgroup they designate Desmothoraca. In the 



Chalarothoraca, Hertwig and Lesser, 



the individual pieces forming the skeleton are in the 

 different species of various forms. They may be, as 

 has been said, either elongate and pointed and scattered, 

 when they are called "spicules;" or radial, when they are 

 called "spines;" or they may form little spherules or tablets, 

 or some of these varieties of skeleton-constituents may be 

 characteristically associated in one and the same species. 

 During inception of food these parts can become pushed 

 aside so as to leave it free opportunity to become passed into 

 the soft body-mass ; so also do they seem to become shunted 

 during "conjugation" or mutual temporary junction of the 

 sarcode of two individuals, as can be seen in Acanthocystis. 

 Excrementitious matter, on being expelled, acts in the same 

 way in pushing aside the loosely associated spines, which 

 soon thereafter regain their position. 



Acanthocystis turfacea. Carter. 



Whilst as mentioned I can quite coincide that the genus 

 Acanthocystis, subordinated to theRadiolaria by its discoverer 

 and other subsequent observers, should not be so but is simply 

 a skeleton-bearing Heliozoan, I cannot at all feel satisfied that 

 Carter's original Acanthocystis turfacea can be specifically 

 identical with either the so-c'dWeH Actinophrys viridis, ^hrenh., 

 or A. brevicirrhis (Perty), the short fimbriate border of either 

 spines (?) or pseudopodia (?) around the periphery of Ehren- 

 berg's figure of the former is so completely unlike Carter's 

 not very uncommon form, hence I must hold that Greeff" and 

 Grenacher are wrong in identifying the form therewith and 

 calling it Acanthocystis viridis ; whilst as regards A. brevi- 



