RECENT MEMOIRS ON FRESHWATER RHIZOPODA. 375 



As in R. viridis, though occasionally occurring singly, the 

 individual body-masses of R. elegans occurred sometimes to 

 the authors combined in colonies ; on the only occasion I 

 have met this species so they occurred to myself; as they 

 describe, the body-masses are mutually united by slender 

 isthmuses of sarcode, yet vastly thicker than pseudopodia, 

 and the whole group immersed in and surrounded by the 

 common spicule-bearing matrix. In such a group, of course, 

 the pseudopodia are mainly given off from the outer portions 

 of the component individuals, though some may be given off 

 inwards, and then may cross, and even inosculate. 



PompJwlyxophrys punicea, Archer. 

 Hyalolampe fenestrata, Greeff. 



Touching the priority of the nomenclature for the fore- 

 going well-marked and not uncommon Heliozoan, I venture 

 to think it must be conceded to my name, for although 

 Greeff's and my papers were published in the same month, 

 the Number of the ' Quarterly Journal of Microscopical 

 Science' was published on the 1st, and if I mistake not the 

 Heft of the ' Archiv fiir Mikroskopische Anatomic ' did not 

 make its appearance till the middle of the month, in which 

 case I should have been in advance only by about a fort- 

 night. 



Hertwig and Lesser without doubt correctly regard the 

 outer stratum of silicious spherules as a skeleton, and in 

 opposition to Greeff, they equally correctly regard these 

 as but loosely connected and readily dissociated (either per- 

 manently by pressure, or temporarily, or even a few per- 

 manently, during inception of food or extrusion of feecal 

 matter). If some pressure be exerted on an example of 

 P. punicea {H. fenestrata, Greeff), so as to break up the 

 body-mass into two portions, each soon appears again rotund 

 and surrounded around the periphery by its share of the 

 spherules (perhaps now only for the most part in a single 

 stratum); still no doubt some are permanently dissociated 

 by the force employed, yet that any at all almost should 

 accompany the disconnected portion of the body-substance 

 and become redistributed around it with so much nicety 

 could, one would suppose, be effected only by being carried 

 over along with and in some medium ; it at least proves that 

 Greeff's original conception was so far inaccurate, that is, 

 that it does not possess a desmothoracous " fenestrate" 

 skeleton. 



Hertwig and Lesser consider the body-mass, densely loaded 



