66 BRITISH FRESHWATER RHIZOPODA. 



applied. Ehrenberg in 1840 described his Diffiugia 

 spiralis thus : " D. lorica subglobosa spirali, super- 

 ficie insequali, pseudopodiis numero variis hyalinis." 

 Schlumberger in 1845 described as Lecquereusia 

 jurassica a form which is certainly that now known as 

 L. spiralis* Ehrenberg in 1872 accepted Schlum- 

 berger's species and gave figures of his own species 

 (spiralis') representing it as sand-covered ' and much 

 less elegant in form than Schlumberger's L. jurassica, 

 thus confirming his previous description of it as 

 having an uneven surface (due to the sand-particles). 

 Rhumbler in 1895 assigned the elegant and compara- 

 tively smooth form with "vermiform pellets" (as Leidy 

 called them) and transparent test to L. spiralis, and 

 named the less elegant rough form with sand-particles 

 and opaque test, L. modesta. He was almost certainly 

 in error in doing so, and should have adopted for the 

 elegant form the name L. jurassica Schlumb., and for 

 the less elegant one that of L. spiralis Ehrenb. To 

 change these names now would create such confusion 

 that advantage is taken of the slight doubt which 

 exists as to the necessity of doing so. The synonymy 

 of the two species is much involved, and probably several 

 references given under Lesquereusia spiralis should 

 be transferred, in whole or part, to L. modestaJ] 



1. Lesquereusia spiralis (Ehrenberg) Biitschli. 

 (Plate XXIII, fig. 8 ; and figs. 73 and 75 in text.) 



Difflugia LECLEEC ? (pars) in Mem. du Mus. II (1815), p. 



447, ff. 1, 4 (noni. la). 

 Difflugia spiralis EHRENBERG ? in Monatsb. Akad. Wiss. 



Berlin, 1840, p. 199 ; BAILEY in Smithson. Contrib. II 



(1851), 8, p. 41 etc.; PRITCHARD Hist. Infus. new ed. 



(1852), p. 208; and ed. 4 (1861), p. 553; FRESENIUS 



* His description is : " Animal a tet resistant, diahpane, grisatre,en forme 

 de cornue globuleuse un peti deprimte ; a cou large et court ; comme compose 

 d'une pate de petits corps bacillaires. Longeur, environ O'l ; largeur, 0'083; 

 epaisseur, 0'066 [mm.] ." He states also that the test is diaphanous so that 

 the body can be easily seen in the interior. This is the earliest clear defini- 

 tion of the species. 



