260 G. T. HARRIS ON THE 



(278) Cosmarium tenue Arch. In the British Isles this species 

 has only been recorded from Ireland. It is certainly- 

 rare on Dartmoor. 



(213) Cosmarium moniliforme (Turp.) Ralfs. The type is quite 

 rare on Dartmoor, but the form panduriformis Heimerl 

 is extremely common. 



(318) Staurastrum Bieneanum Rabenh. This desmid appears to 

 be quite local on Dartmoor, but was frequent in Merripit 

 bog. Typical specimens, however, were infrequent, 

 and tetragonal forms quite as plentiful as the normal 

 triangular. 



(332) Staurastrum ellipticum West. Apparently confined to one 

 bog in the Lydford district. This was a bog of some 

 extent on the eastern slope of Hare Tor, above the 

 Rattlebrook ; here it was in some abundance. 



(343) Staurastrum grande Bulnh. var. farvum West. Only one 

 or two specimens were observed of this desmid from the 

 extensive Merripit bog. 



(380) Staurastrum striolatum (Nag.) Arch. Typical St. strio- 

 latum occurs generally on Dartmoor, but is very infre- 

 quent even in the bogs in which it occurs. 



(329) Staurastrum dispar (Breb.). Teste, Professor G. S. West. 

 Roy seems to have been the only one to record this 

 species for English stations. It is somewhat frequent 

 on Dartmoor in the larger bogs. 



(314) Staurastrum alternans var. fulchrum Wille. Teste, Pro- 

 fessor G. S. West. Apparently a northern variety 

 recorded by West from the north of Scotland. 



(377) Staurastrum retusum Turn. var. horeale W. and G. S. West. 

 Teste, Professor G. S. West. This small species appears 

 to have been known hitherto only from the Orkney and 

 Shetland Islands. It is very rare on Dartmoor and 

 occurred only in two places at a considerable elevation. 



(275) Cosmarium tatricum var. sphaeruliferum West. So far this 

 desmid has only been recorded from Co. Galway. 



(192) Cosmarium jurcatosfcrmum W. and G. S. West. This 

 species, only recorded by West from the Orkneys and 

 Lough Neagh, occurs very sparingly in some of the 



