558 Annals of the South African Museum. 



one or both semieells. were always to be found (Fi^. 29, a-d). These 

 three species are, however, all distinguished by having an end-view 

 without a trace of median inflation, whereas all the types of cell-form 

 shown in Fig. 29 had an end-view with a slight median enlargement ; 

 in fact, although large numbers <>i' individuals were examined, all 

 showed this character quite distinctly. It may be mentioned that the 

 end-view was. in general, much more like that shown by Messrs. West 

 in Fig. 11 {Inc. cit., PI. C) than that depicted by Schmidle. A peculiar 

 form of end-view, with flattened poles, only noticed in connection with 

 a front-view of the conspersum-tvpe, is seen in Fig. 29, e" . 



As regards the granulation, the granules were, in the vast 'majority 

 of cases, of the fine type figured by Schmidle and Messrs. West. In 

 sample 48, however, occasional individuals with a coarser granulation, 

 more like that of C. quadrum, Lund., were observed; some of these 

 individuals also showed reduction of the granulation in the middle of 

 the apex, such as is characteristic for this species. In correspondence 

 with the larger size of the specimens (c/. below), the granules were 

 more numerous than in Schmidle's or Messrs. West's forms. More- 

 over they covered practically the whole surface of the semicells in a 

 uniform manner. In general they were arranged in concentric series 

 (Fig. 29, a), as in Messrs. West's specimens, although occasional 

 individuals showed them in more or less obvious vertical series. 



These diverse forms may be enumerated as follows : 



(a) Forma typica (Fig. 29, a, e) : Long.. 48-52 /a ; lat., 47-50 fi ; 

 lat. isthm., 14-15 // ; crass., 22 -24//. Dimensions of individual speci- 

 mens: 48 x 49, 52 x 48, 50 x 47, 51 x 50, 48 x 48, 50 x 50 //. 



(b) Forma pseudo-quadrum (Fig. 29, l>, it, e r ) : Long., 48-51//: 

 lat., 44-49 fx. ; lat. isthm.. 18—15 yw.. Dimensions of individual speci- 

 mens, 48 x 48, 51 x 50, 48 x 49, 48 x 44 //. 



(c) Forma psetido-conspersum (Fig. 29, c, <■', e") : Long., 47//: 

 lat.. 48 /u ; lat. isthm., 14//. 



In view of the fact that a la rge percentage uf the individuals showed 

 a shape in front-view vqvv similar to that of C. quadrum, Lund. 

 (including even a faintly ret use apex in some cases. Fig. 29, </), the 

 question arises as to whether ('. suhbroomei, Schmidle, would not better 

 be regarded as a variety of C. quadrum, Lund., with several forms. It 

 may be well, however, to await further observations before arriving at 

 a definite conclusion on this point. 



Var. pseudo-pearsoni, nov. var. (Fig. 30). 



Differt a typo cellulis ca. 1 ' plo longioribus quam latis, semicellulis 

 ovato-pyramidatis. lateribus convexis et convergentibus, apice indis- 

 tincte truncato, granulis parvis numerosis in seriebus confertis con- 



