258 G. T. HARRIS ON THE 



(9) Spirotaenia minuta Thur. Only three British stations are 



mentioned in West's Desmidiaceae for this desmid, one 



of them being in Cornwall. 

 (8) Spirotaenia ehoracensis G. S. West. The only record hitherto 



is Professor G. S. West's of Cam Fell, W. Yorkshire 



{Teste, Professor G. S. West). 



(11) Spirotaenia traheculata A. Br. (Teste, Professor G. S. West). 



Lough Anna, Donegal, is the only British locality West 

 gives for this desmid. A few specimens were collected 

 from one of the Metherall bogs. 



(12) Mesotaenium Be Greyi Turn. Although it is stated that 



this species occurs, in common with most of the 

 Mesotaenia, in mucilaginous masses on rock surfaces, 

 it is met with on Dartmoor more or less free in the bogs. 



(19) Cylindrocystis minutissima Turn. Lough Neagh. Ireland is 

 the only British locality given for this desmid in West's 

 Desmidiaceae. The Dartmoor specimens rather exceed 

 the measurements given by West, being 15 /x x 10 /x. 



(23) Netrium interruptum var. sectum W. and G. S. West. 

 Hitherto only recorded from Westport, Co. Mayo. 



(43) Penium navicula var. crassum W. and G. S. West, from 

 Postbridge, is a variety which has so far only been 

 recorded from the extreme north-west of Scotland 

 {Teste, Professor G. S. West). 



(34) Penium exiguum West is another species hitherto only 

 recorded from the south-west of Scotland. It is widely 

 spread on Dartmoor but very infrequent. 



(46) Penium spirostriolatum Barker. This interesting desmid is 

 generally distributed over Dartmoor and comparatively 

 plentiful in some of the larger bogs. 



(74) Closterium incurvum Breb. This rare desmid was collected 

 at one or two stations on Dartmoor, but appears to be 

 more at home at a lower altitude, as I have collected 

 it in large quantities in some of the small ponds of 

 East Devon. 



(58) Closterium acerosum (Schrank) Ehrenb. is another low- 

 land species rarely occurring on Dartmoor, but abundant 

 in the low-lying portions of the county. 



