RECENT MEMOIRS ON FRESHWATER RHIZOPODA. 349 



say that through this " porous^' coat not only the pseudo- 

 podia proceed outwards, but also more or less large corpuscles 

 are able to pass, so that he was inclined to assume that the 

 coat possessed " certain larger openings or was in part 

 formed of a soft permeable organic substance." He fui'ther on 

 says that the extremely fine pseudopodia can, as in the other 

 species, with readiness be followed, through what he now 

 calls the " outer protoplasma-ring," up to and into the body. 

 He records a " central globular structure" (doubtless truly 

 "nucleus"), though in A. ruber (see fig. 3) he could find no 

 " central vesicle or nuclear structure." 



Hertwig and Lesser describe under the name Hyalolampe 

 exigua a form which appears mainly to be distinguished from 

 H. fenestrata, GreefF = PompJiolyxophrys punicea, Archer 

 (see hereafter) only by its greater minuteness and the greater 

 delicacy of the "skeleton," the spherules of which are superim- 

 posed in more numeronslayers. Their contours can only be dis ■ 

 cerned under a very high amplification. The authors mention 

 that frequently one pre-eminently large pigment-granule was 

 often present, sharply contoured, globular, and of a ruby-red. 



The authors think it highly probable that this form may 

 be identical with that named Astroclisculus ruber by GreefF 

 (see PI. XXI, fig. 3), which, except as regards the outer 

 *' skeleton," really seems to present much resemblance; 

 GreefF describes the outer envelope in his form as present- 

 ing a slightly granular but otherwise hyaline " sarcode " 

 stratum, which, as mentioned, he regarded as outwardly 

 porous and silicious, the pseudopodia making their way out 

 through the supposed pores. Having regard to the great 

 difficulty of recognising the composition of this outer skeleton 

 in Hertwig and Lesser's form, which under insufficient am- 

 plification might appear homogeneous, it is quite conceivable 

 that these authors may be correct in their supposition of 

 the identity of GreefF's form with theirs ; but, could this be 

 proven, should not GreefF's specific name (just as applicable) 

 hold good ? (or, rather, should not the form in question 

 stand as Pompliolyxophrys rubra, GreefF?) 



Hertwig and Lesser, indeed, are inclined to go further, and 

 conjecture that all the forms referred to his genus Astroclis- 

 culus, differing, as they do, only in colour (a somewhat 

 variable characteristic) may be referable to their H. exigua. 

 I am myself inclined to doubt the propriety of this assump- 

 tion, although forms seemingly referable to Astrodisculus 

 being, in my own experience, amongst the very greatest rari- 

 ties, and, when found, so scanty, T have been unable to 

 submit them to any experiment. Although Hertwig and 



