6 
Transactions of the Society 
Closterimn didymotocum Cord., H, D. 
„ lunula Ehrb., H. 
„ turgidum Ehrb., H. 
„ Ebrenbergii Men., D. 
„ Dianae Ebrb., H, D. 
„ angustatum Ktz., H, D. 
„ rostratum Ebrb., H. 
„ setaceum Ebrb,, H, D. 
* „ Kutzingii Breb., H. 
Although given in Cooke s ‘ British Desmids,’ no locality is 
recorded for this species. 
Closterium intermedium Ealfs, D. 
„ cornu Ebrb., H. 
„ acutum Breb., H. 
„ aciculare West, D. 
„ linea Pert., H. 
Micrasterias denticulata Breb., H, D. 
„ „ var. INTERMEDIA n. var., D, Fig. 8. 
Length of frond about 200 />t, breadth about 180 />t. This variety 
appears to be intermediate between M. denticulata Breb. and M. 
Thomasiana Arch. The size and the segmenting correspond closely 
to those of the typical form, the dentation of the edge being decidedly 
more apiculate, resembling that of M. Thomasiana ; but it is 
destitute of the apiculate elevations ” and remarkable divergent 
projections ” in the centre described as characteristic of this species. 
It is, however, very doubtful whether M. Thomasiana should be 
retained as a distinct species. Its extreme form appears to have been 
seen by no one but its discoverer. Jacobsen (Desm. Denm., in Bot. 
Tidskr., 1874, p. 186) regards it as a variety of M. denticulata, and 
describes a series of intermediate forms with the projections more or 
less developed. The present variety occurred in bog-pools on 
Dartmoor. 
Micrasterias rotata Ealfs, H, D. 
„ „ var. URNiGERA n. var., H. Fig. 9. 
This beautiful desmid differs from the typical form in its larger 
size, and in the urn-like form of its central lobe, which projects as 
much as 25 n beyond the lateral ones. In this respect it resembles 
Ealfs’s draw ng more nearly than Cooke’s. Wolle (Desmids U.S., 
pi. xxiv. f 1) also depicts the central lobe as projecting considerably. 
The surface of the frond is covered with inflated protuberances. The 
extreme length, including the projection, is 325 ya, the greatest 
breadth 250 ya ; but in the specimens observed the two halves were of 
very unequal size. Bog near Lyndhurst. 
