LITHOCOLLA. 45 



consisting of grains of sand and diatom frustules ; 

 nucleus single, placed eccentrically. 



Two species are included in this genus, L. globosa 

 F. E. Schulze and L. flavescens Penard ; ElaiorlwinN 

 arenosa, Frenzel (LiihospJiserella arenosa Schaudinn) is 

 probably a synonym for the former, whilst the marine 

 species Raphidiophrys arenosa Gruber* has much 

 resemblance to the latter. 



Some authorities consider that the differences 

 between the genera Lithocolla and Elseorhanis are 

 insufficient to warrant their being separated ; their 

 exact position among the Heliozoa or Pseudo-heliozoa 

 is also still open to question. 



Only L. globosa has been recorded from the British Isles 

 L. flavescens (Penard) is much smaller, measuring about 18 /u. 

 in diameter over the outer envelope, which consists of very 

 minute silicious grains. 



Lithocolla globosa F. E. Schulze. 



. 



(Text-fig. 188.) 



Lithocolla globosa 



F. E. SCHULZE Arch, niikr. Anat. X, 1874, p. 389, pi. xxvi, if. 6-10. 

 ARCHER Qrt. Jrn. Micr. Sci. (N.S.) XYI, 1876, pi. xxi, f. 9. 

 PENARD Jahrb. Nassaii. Yer. Naturk. XLIII, 1890. p. 17. pi. i. f 12 

 WEST Jrn. Linn. Soc. Zool. XXVIII, 1901, p. 338. 

 PENARD Heliozoaires, 1904, p. 216, fig. 

 ZYKOFF Zool. Anz. XXV, 1902, p. 178. 



Body spherical ; outer envelope composed mostly of 

 sand grains and diatom frustules cemented together ; 

 ectoplasm of a more or less pronounced reddish colour, 

 of a liquid consistency, containing numerous small 

 coloured granules, also frequently food particles and 

 diatoms ; endoplasm not differentiated ; nucleus large, 

 containing a single central nucleolus, placed -eccen- 

 trically ; no contractile vesicle but often a large 

 vacuole present ; pseudopodia tenuous, not long*, finely 

 granuliferous ; central granule not observed. 



* ' Nova Acta Acad. Leop. Carol./ XLVI, 1884, p. 507, pi. ix, fig. 34 a, b. 



