PLACOCISTA JURASSICA. 47 



Test smaller than in the preceding species and of 

 broader proportions, being sub-circular to ovoid in 

 broad view ; transverse section lenticular ; furnished 

 with acicular spines of various lengths which cover 

 the whole surface of the test but are less numerous 

 on the central portions ; body-scales sub-circular or 

 broadly oval, regularly imbricated ; aperture-scales 

 sub-circular, forming undulate margins to the linear 

 aperture ; nucleus large, containing from one to 

 three nucleoles ; contractile vesicles obscure, usually 

 two or more ; plasma colourless ; pseudopodia not 

 observed. 



Length 70-76 /A; breadth 50-54 /A; aperture 20- 

 28 /A; thickness about half the breadth; nucleus 17- 

 20 fji in diameter ; spines 6-18 /a in length. 



Habitat. Sphagnum. Rare. 



ENGLAND. Harrop Tarn, Cumberland (Brown] ; 

 Chat Moss, Lancashire (Gash) ; Leckby Carr, N. 

 Yorkshire. 



WALES. Snowdon,' Carnarvonshire (Sounders, coll.). 



SCOTLAND. St. Kilda, Outer Hebrides (Brown); 

 Pentland Hills (Cash) ; Stranraer, Wigtownshire 

 (Brown}. 



The spines may be solitary or in tufts of two to 

 four (PL XLII, fig. 1); they are never flattened; 

 they may vary considerably in numbers and length. 

 The test is often opaque and rarely glabrous. 



3. Placocista lens Penard. 

 (Plate XL, fig. 10.) 



Euqlypha lens 



PENARD in Rev. Suisse Zool. VII (1899), pp. 78-79, 115, pi. vii, ff. 



20-24 ; op. cit. IX (1901), pp. 234, 237. 

 FOREL Le Leman, III (1904), p. 137. 

 Placocysta lens 



PENARD Faune Rhiz. Leman (1902), pp. 514-515, 3 figs. ; Sarcodines 

 grands Lacs (1905), pp. 56-57, 109, 110, 2 figs. ; Sarcodines in Cat. 

 Invert. Suisse (1905), p. 106; in Proc. Roy. Soc. Edinb. XXY 

 (1905), pp. 595, 603-604, 608. 



