LITHOCOLLA. 46 



consisting of grains of sand and diatom frustules ; 

 nucleus single, placed eccentrically. 

 **^ Two species are included in this genus, L. globosa 

 F. B. Schulze and. L. flavescens Penard ; Elseorhanis 

 arenosa Frenzel {Lithosphserella, arenosa Schaudinn) is 

 probably a synonym for the former, whilst the marine 

 species Baphidiophrys arenosa Glruber* has much 

 resemblance to the latter. 



Some authorities consider that the differences 

 between the genera LithoeoUa and Elseorhanis are 

 insuflficient to warrant their being separated ; their 

 exact position among the Heliozoa or Pseudo-heliozoa 

 is also still open to question. 



Only L. glohosa lias been recorded from the British Isles ; 

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

 in diameter over the outer envelope, which consists of very- 

 minute silicious grains. 



Lithocolla globosa F. E. Schulze. 

 (Text-fig. 188.) 



Lithocolla glohosa 



P. E. Schulze Arcli. mikr. Anat. X, 1874, p. 389, pi. xxvi, S. 6-10. 

 Aechbe Qrt. Jrn. Micr. Sci. (n.s.) XYI, 1876, pi. xxi, f. 9. 

 Penaed Jahrb. Nassau. Ver. Naturk. XLIII, i890, p. 17, pi. i, f. 12. 

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

 Penaed Heliozoaires, 1904, p. 216, fig. 

 Ztkofe Zool. Anz. XXT, 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, h. 



