290 THE FRESH-WATER ALG^ OF NORTH YORKSHIRE. 



such as Desmidium Swartzii Ralfs, Xanthidium armatum Breb., and 

 Arthrodesmus convergens Ehrbg. A. Incus Hass. was very scarce. 

 On the other hand, some rare species are frequent, as Cosmarium 

 tetrcujonum Nag., C. cyclieum Lund., C. quadrifarium Lund., forma 

 hexasticha Nord. (C. hexastichum Lund.), C. suhspeciosum Nord., 

 Staiirastrum acarides Nord., &c. 



The following contractions are used for the six localities quoted 

 most often : — 



M. for Miclde Fell. Sc. for Scarborough Mere. 



C. for Cronldey Fell. Se. for Seamer. 



S. for Great Shunnor Fell. St. for Strensall. 

 The sequence of the Diatoms is after Rabenhorst ; the rest are 

 arranged in accordance with the method adopted in Cooke's works. 



Class CHLOROPHYLLOPHYCE^. 



Order Coccophyce^e. 



Family Palmellace-e. 



Eremosp/tcem viridis D. By. M., C. 



Fleurococeus vuhjaris Meneg. Common. 



Gheocystis ampla Kg. M. — G. vesiculosa Nag. St. — G. hotry- 

 oides Kg. M. 



Schizochlamys gelatinosa A. Br. St. 



Falmella mucosa Kg. C, S., Sc, Cotterdale. — P. hyalina Breb. 

 Sc, Cotterdale. 



Tetraspora gelatinosa (Vauch.). Levisham. — T, lubnca Roth. S. 



Botryococcus Braunii Kg. S. 



Apiocystis Brauniana Nag. Sc. 



Ehaphidium acicidare A. Br. Sc, Muker, Masham. — B.falcatum 

 (Corda) Cooke. C, Sc 



Dictyosphoenum Ehrenhergianmn Nag. Sc, M., St. 



Pahnodactylon suhrauiusum Nag. S., C. 



Nephrocytmm Agardhianum Nag. M. — N. Ndgelii Grun. M, 



Family Protococcace^. 



Protococcus viridis Ag. Common. 



Chlorococcum gigas Gvun. S., Sc 



Pohjednum tetradricum Nag. M. — P. longispimim Rabh. M. — 

 P. eiwrme Rabh. M. 



Scenedesmiis ohtusiis Meyen. M., Sc. — S. acutus Meyen. M., 

 C, Sc — Var. ohliqims Rabh. Sc. — S. antennatus Breb. Sc. — S. 

 quadricauda Breb. M., Sc. 



Pediastrum aiigulusum Ehrbg. Sc — P. Boryanum Turp. ^I., 

 So. — P. pertiisum Kg. Sc. — P. Ehrenbergii A. Br. Sc 



Ccelastrum microsporum. A. Br. Sc 



Hydrianum heteromorphum Reinsch. M., Sc. 



Family Volvocine^. 



Chlamyducoccus phirialis A. Br. Sc, Sc, Cotterdale, 

 Pandorina monim Bory. C. 

 Gonium pectorale Mxdl, S., Sc 



