42 
Transactions of the Royal Society of So2ith Africa. 
cell., 21-38 /x; lat. cell., 18-29 /x ; lat. isthm., 5-6-5 /x ; crass., 14-18 /x 
(Fig. 15). 
var. a, forma minor aiigulis basalibus rectangularibus, marginibus 
lateralibiis superioribus convergentibus crista mediana retusa vel etiam 
emarginata munitis, marginibus lateralibus inferioribus varie crenatis sub- 
parallelis. Long, cell., 21-22 /x (raro usque 27 fx, vel etiam 30 /x) ; lat. 
cell., 18-19 /X (raro usque 25 /x) ; lat. isthm., 5-6 /x ; crass., 14-15 /x. Hac 
varietas ad typum appropinquat (Fig. 15, VIII-X). 
Formae apicibus plus minus distincte delimitatis, crenis in parte 
inferiore marginium lateralium parum efformatis (Fig. 15, YI, VII, XI). 
Pro parte ad var. accedens. 
Forma, W. West, Alg. W. Ireland, 1891 {loc. cit.). 
var. /), forma major marginibus lateralibus plus minus convexis, a basi 
ad apicem gradatim convergentibus, crenis marginium lateralium frequen- 
tioribus aequalibus vel subaecjualibus. Long, cell., 30-33 /x ; lat. cell., 
27-29 /X (raro 24 ii) ; lat. isthm., 6-6*5 ; crass., 15-18 Hac varietas a 
tjpo plus discedit (Fig. 15, I, II, Y). 
Forma' marginibus lateralibus superioribus cristis retusis vel truncatis 
duabus (Fig. 15, III). 
Forma crenis superioribus marginium lateralium majoribus (Fig. 15, 
IV). 
Yar. occultnm (Sclimidle), 1902 (loc. cit.), forma minor marginibus 
lateralibus convergentibus, apicibus paullo protrusis leniter undulatis ; 
marginibus lateralibus superioribus crista mediana paullo emarginata 
munitis; in media semicellula granulis nullis. Long, cell., 22 ^; lat. cell., 
20 ^i. 
A curious abnormality observed among these forms of C. subprotuniiclnm 
is shown in Fig. 16, A. 
17. Cosmarium caJcareum, Wittr. : W. & G. S. West, loc. cit., p. 285, 
Pl.LXXXYII, figs. 1, 2. 
Samples 811, 812, and 315. 
Long, cell., 24/x; lat. cell., 18-20 /x ; lat. isthm., 6 fx. 
18. Cosmarium hotrytis, Menegh. ; W. & G. S. West, op. cit., iv, 1912, 
p. 1, PI. XGYI, figs. 1, 2, 5-15. 
Sample 159 (very rare). 
Long, cell., 63-68 ; lat. cell, 57 ; lat. isthm., 18-21 /x. 
Previously recorded from the Karoo (CI. S. West), Cape Colony and 
Orange Free State (Fritsch). 
Ycir. pegleri, F. E. Fritsch, nov. var. (Fig. 17). 
Celluiis granulis majoribus frequentioribus. apicibus evidenter truncatis 
vel etiam retusis, a vertice visis polls subdeplanatis, a latere visis marginibus 
