28 
Transactions of the Eoyal Society of South Africa. 
2. Euastrum sim])liciforme, F. E. Fritsch, n. sp. (Fig. 9). 
E. subparvum, circiter 2plo longius quam latum, subprofunde con- 
strictum sinu subangusto-lineari extus paullo ampliato. Semicellulae 
trapeziformes, apice leniter concavo vel interdum triundulato, lateribus 
leniter convergeiitibus tricrenatis (angulis apicalibus inclusis), crenis 
superioribus prope apice, crenis inferioribus ca. in media parte marginis 
lateralis ; angulis basalibus subrectangulari-rotundatis. Membrana in 
tota superficie semicellulae glabra. A latere visae ellipticae, apice sub- 
rotundato, intra marginem lateralem lineis duabus cum crenis lateralibus 
Fig. 9. — Euastrum simplicifoniie, F. E. Fritscli, n. sp. a, front-, h, end-, and c, 
side-views, x 1100. 
in aspectu frontale congruentibus. A vertice visae subellipticae, polls 
deplanatis retusis, inflatione mediana subdistincta. 
Long, cell., 40-42 /x; lat. cell., 21-24 /x; lat. isthm., 9 fi; crass., 15-16 /x. 
Sample 327 (very rare). 
This species might almost equally well be regarded as belonging to the 
genus Cosmarium, the chief reasons for referring it to Euastrum lying 
in the character of the side-view and the usual concavity of the apex of 
the semi-cell. As a matter of fact it shows considerable resemblance to 
Cosmarium angulatum, Perty, a sj^ecies which is not at all well known. 
It differs from the latter in having a narrower isthmus and in the character 
of the lateral margins ; the end-view, which is not known in the case of 
Cosmarium angulatum, also appears distinctive. 
