114 W. ARCHER. 



whilst at same time they are even more subject to variation 

 in shape and size, and are often somewhat rudely applied and 

 even in the living animal more prone to becgme dislocated. 

 They sometimes show a thickened " frame-like" edge which 

 forms a narrow rimlike border, or it may be so extended as to 

 leave but a minute square in the middle, but mostly they are 

 alike throughout. They mostly run in lines longitudinally 

 (taking the " mouth" as the anterior end) and transversely 

 at right angles, but sometimes obliquely; still the ordinary 

 contour is ever maintained. This form sometimes showed a few 

 spines comparable to those of a Euglypha, but this rarely; 

 but I could not make out the place of origin of these, 

 whether they occur between the plates (that is, of indepen- 

 dent origin), or as processes given off from certain of them 

 (which is more likely). This point would deserve attention 

 should the spiniferous form again present itself. 



Difflugia acropodia, Hertwig and Lesser.^ 



Under foregoing name the authors record a well-marked 

 Difilugian of rounded figure which they say is not common 

 (diam. 0*05 mm.). It consists of a homogeneous pellucid 

 membrane, the foreign attached objects for the most part 

 consist of quartz-granules, with sometimes a few diatoma- 

 ceous frustules, mostly loosely fixed, that is, leaving con- 

 siderable irregular intervals, though sometimes more crowded 

 and completely covering the test. But the greatest distinc- 

 tion of the present from other species of Difflugia is in the 

 form of the pseudopodia, which are not blunt finger-like pro- 

 longations, but form long more or less distinctly conical plates, 

 running into variously lobed and subdivided shapes, always 

 rather acutely pointed at the apices ; sometimes one may 

 run out long and comparatively thin (as it were subulate), 

 almost resembling a pseudopodium of an Actinosphserium, 

 but here the pseudopodia are always homogeneous, never 

 granular. They fitfully branch, and on contact may oc- 

 casionally anastomose, even as they ramify with the ten- 

 dency to become flattened out, or two may appear to coalesce 

 by the running up between of a membrane-like continuation 

 of plasma, soon to be retracted or modified in contour, so fluent 

 is the movement of this form and so manifold the changes 

 of its pseudopodial region. Sometimes, indeed, a finger-like 

 projection can be seen amongst those described, but the 

 authors seem inclined to regard this rather as indications of 



' Hertwig and Lesser, loo. cit., p. 1]7, t. ii, f. 6. 



