112 BRITISH FRESHWATER RHIZOPODA. 



these aggregations of diatoms are held together by the 

 transparent cuticles of Lecythium granulatum, the 

 enclosed plasma having decayed away or even being 

 still present and living but escaping observation -(vide 

 PL XLIV, fig. 11); he also raises the question as to 

 whether the diatoms live in symbiotic relationship with 

 the 'Lecythium or are retained in a living state to serve 

 as food as need may arise. 



Both conjugation and longitudinal division have been 

 observed to take place in this species. 



L. avidum Leidy-is very similar and may be a large 

 form or variety of this species, it measures 1 48-220 p, 

 in length. L. curviiin Leidy appears to be identical 

 with this species. 



4. Lecythium spinosum (Penard) Hopk. 

 (Plate L, figs. 3-6.) 



Trinema spiuosum 

 PENARD in Mem. Soc. Geneve, XXXI, i, n (1890), pp. 186-187, pi. x, 



ff. 72-74. 

 Pampliaqus armatus 



LAUTERBORN in Zool. Anzieg. XXIX (1901), p. 54 ; in Zeits. wiss. 



Zool. XC (1908), p. 647, pi. xli, f. 3. 

 PENARD (? = Trinema spinosum) Faune Rliiz. Leman (1902), pp. 577- 



578, f. 12 (p. 572). 

 SCHOUTEDEN in Ann. Biol. lacustre, I (1906), pp. 360, 361. 



Test membranous, ovoid or pyriform, unsymme- 

 trically compressed, furnished with short curved 

 spines; aperture sub-terminal, oblique; nucleus gran- 

 ular, placed posteriorly ; plasma filling the test, pseudo- 

 podia numerous, simple or branched. 



Length 45-70 JJL; breadth about half the length. 



Habitat. Aquatic vegetation. Rare. 



ENGLAND. Wansted Park, Epping Forest, Essex 



(Scorn-field} . 



The figures on Plate L are from sketches supplied by 

 Mr. Scourfield, who adds the following description : 

 " Tests armed with spines, the contents yellowish- 

 green with highly-refringent globules; pseudopodia 



