PSEUDOCHLAMYS. 129 



Genus 16. PSEUDOCHLAMYS ClaparMe & Lacli- 

 mann, 1859. 



Pseudochlamys CLAPAREPE & LACHMANN Etudes Inf. et 



Rhiz. 2 (1859), p. 443. 

 Amphizonella GREEFF in Arch. f. mikr. Anat. II (1866), 



p. 323. 



Test discoid, flexible when young, protecting the 

 plasma-body, which contains a central nucleus and 

 several contractile vesicles. 



This genus was established by Claparede and Lach- 

 mann (loc. cit.) to include a minute and highly-curious 

 Arcella-like organism! 1 Ordinarily the test is smooth, 

 and, in the young state, quite transparent, but it 

 becomes brown with age, most deeply coloured in the 

 centre, and shading off towards the margin, sometimes 

 appearing " faceted or punctate " according to these 

 authors. Hertwig and Lesser (' Arch, fiir mikr. Anat.,' 

 1874) represent the concavity of the test, which in 

 general shape resembles a watch-glass, as being closed, 

 all but a central opening, by a delicate and hyaline 

 continuation of the rim, completing the external 

 resemblance to Arcella. Penard figures the same 

 (' Faune Rhiz. du Bassin du Leman,' p. 181). The 

 peripheral membrane is so exceedingly attenuated 

 that the structure referred to is very difficult to make 

 out. In the scores of empty tests we have examined, 

 only in one instance did we find the faintest semblance 

 of a central opening. 



1. Pseudochlamys patella Claparede & Lachmann. 

 (Plate XVI, figs. 1-9.) 



Pseudochlamys patella CLAPAREDE & LACHMANN fetudes Inf. 

 et Rhiz. 2 (1859), p. 443, t, xxii, f. 5 ; CARPENTKK 

 Forain. (1862, Ray Soc.),p. 25; HERTWIG & LESSER in 

 Arch. f. mikr. Anat. X (1874), Suppl. p. 100, t. iii, f. 1 ; 

 F. E. SCHULZE in Arch. f. mikr. Anat. XI (1875), p. 332, 

 t. xviii, ff. 7-14; ALLMAN in Journ. Linn. Soc., Zool. XIII 

 (1877), p. 393, f. 3; ARCHER in Q. J. Micr. Sci. XVII, 



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