346 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



" central capsule," or structure homologous thereto ; the 

 rounded bodies seen in their sarcode, and sometimes re- 

 garded as a central capsule, are not to be interpreted as such ; 

 nor do they possess structures homologous to the " yellow 

 cells of the Radiolaria.^'' This is also the view of Drs. Hert- 

 wig and Lisser, in their memoir in Schulte's ^?'cAfye5, 1874, 

 S)upp.^ and in the main of Mr. Archer. Still, as we know 

 nothing, or at least very little, of the developmental history 

 of the two classes, it is possible that an affinity between 

 jRadiolaria and Hellozoa may be demonstrable demon- 

 strated at present it is not. The Heliozoa^ then, are an inde- 

 pendent class of unicellular (though sometimes, rarely, multo- 

 nucleated) organisms. Their fundamental form a sphere, a 

 very few fixed by a stipes. The protoplasm, of which alone 

 the soft part of the body is wholly composed, is differenti- 

 ated into an endosarc and ectosarc, more or less pronounced. 

 In the endosarc constantly lie the nuclei ; if the nucleus (as 

 mostly) is simple, it is more or less excentric ; if there be 

 numerous nuclei, they are irregularly scattered. The ecto- 

 sarc is characterized by the possession of contractile vacu- 

 oles (not yet demonstrable in all species). The pseudopo- 

 dia, serving both for the capture of nutriment and for loco- 

 motion, are thin and filiform, originating all around the 

 superficies of the globular body ; sometimes homogeneous, 

 and sometimes granules pass along them slowly up and 

 down. In many of the Heliozoa is an extremely delicate 

 axis, passing down the pseudoj^odium to the endosarc as a 

 strengthening apparatus, but not at all homologous with the 

 spines of the Acanthometrida^ as Greef has suggested. In 

 the paper we have alluded to, Mr. Archer considers the two 

 genera* of the Heliozoa Askelata, Acthiophrys and Actino- 

 sjjhceman. The resemblance between these is considerable, 

 but in the former the nucleus is always single, in the latter 

 there are numerous nuclei ; in the latter the two regions, 

 both alveolar, are distinctly marked, in the former the endo- 

 sarc is homogeneous, passing by degrees into the vacuolar 

 ectosarc. Quart. Jour, of Mic. Science^ J^dy, 1876. 



