354 W. AECHER. 



suppose to presume that Hertwig and Lesser regard it as void 

 of living substance, and possibly retaining only water. 

 This may be so in older specimens, but one must suppose 

 there vras once a mutual genetic connection. But I should 

 rather myself suppose this is only a narrow region of the 

 outer envelope of a highly pellucid character. 



Heterophrys marina, Hertwig and Lesser.^ (PL XXII, fig. 13.) 



As indicated by the specific name, the authors found this 

 form in sea-water; hoAvever, a single example of one in 

 which I could see no tangible distinction therefrom, as men- 

 tioned, occurred to me in a gathering made from a moor 

 pool, a further evidence, so far as it goes, in favour of those 

 authors' arguments above referred to, and against the pre- 

 sumption that freshwater Heliozoa may be but primitive forms, 

 or even a more lowly group, of Radiolaria. As regards the 

 body-mass in this form, the authors see the differentiation of 

 a homogeneous endo- (fig. 13, ^) and a granular ectosarc 

 (fig. 13, r), to be equally well marked as in Acanthocystis, 

 which can be here all the more readily observed owing to the 

 absence of chlorophyll-granules, the endosarc bearing only 

 colourless rounded granules of varying sizes and sharply 

 contoured crystals belonging to the rhombic system. They 

 did not observe contractile vacuoles, nor did any show them- 

 selves in my own (single) example. There is a submedian 

 oval nucleus, with nucleolus, immersed in the endosarc 

 (fig. 13, ii). The pseudopodia are in length about twice the 

 body-diameter, numerous, and granuliferous. 



Coming to the external region, the authors, in accordance 

 with their views, call it " skeleton," and this presents the 

 same fimbriated periphery (" spines," Hertwig and Lesser) 

 as that of Heterophrys niyriopoda, mihi. See remarks above 

 on this part of the structure, as regards indeed the only ex- 

 ample of this form I have met with, and fiom the fresh- 

 water (if, indeed, it can be truly the same). In fact, except 

 for the marine habitat, smaller size, absence of chlorophyll- 

 granules, pale (not slightly brownish tinted) outer region, 

 and comparatively longer pseudopodia, the authors would 

 have felt inclined to refer it to H. rmjriopoda, mihi ; the dis- 

 covery of a colourless form in the freshwater, so closely resem- 

 bling their form, renders it indeed most probable that so it 

 should be. In Acanthocystis turfacea the presence of the 

 chlorophyll-granules is not constant, though pale examples 

 are but rarely met Avith; I have more than once seen speci- 



^ Hertwig and Lesser, loc. cit., p. 213, t. iv, f. 4. 



