THE FRESH- WATER ALG^ OF NORTH YORKSHIRE. 291 



Order Zygophyce-e. 

 Family Desmidie^. 



Gonatozygon Brebissonii D. By. S., St. 



G. Iseve, n. sp. Joints narrowly fusiform, 7-20 times as long 

 as broad, and quite smooth ; ends slightly dilated. Endochrome as 

 in G. Brebissonii D. By. 5-8 /x broad. I should not have separated 

 this species from the last, but for its smooth cytioderm. This was 

 frequently seen. M. Fig. 6. 



SphcErozosma pygmaum Cooke. M. — S. excavatum Ealfs. M. 



Hyalotheca dissiiicns Ealfs. M., C, S. — Var. Hans WoUe. C. — 

 H. mucosa Ralfs. C. 



Bambusina Brebissonii Kg. M. 



Docidiuyn Ehrenbergii Ralfs. S., C, St. — N2iX. granulatmn^dXis,. 

 C, S. — D. clavatum Kg. S., C. — D. truncatum Breb. St. — D. 

 nodulosum Br^b. C, M., Rokeby. — D. minutum Ralfs. M. 



Closteriuni obtusum Breb. St. — C. Lumda Ehrbg. C, Sc, M. 

 — C. Cucumis Ehrbg. M. — C. acerosum Ehrbg. Frequent. — C. 

 hinceolatum Kg. Frequent. — C. turgidum Ehrbg. S. — C. gracile 

 Breb. S. — C. Ehrenbergii Meneg. Frequent. — C. moniliferum 

 Ehrbg. Frequent. — C. jenneri Ralfs. M. — C. Leibleinii Kg. M., 

 Sc. — C. DiancB Ehrbg. Frequent. -- C. parvidum Nag. St. — C. 

 Venus Kg. M., St., Sc. — C. costatum Corda. M., S., St. — C. strio- 

 latum Ehrbg. M., C, S., St., Se. — C. intermedium Ralfs. S. — 

 C. juncidum Ralfs. C. — C. lineatmn Ehrbg. M. — C. rostratum 

 Ehrbg. St., C, S. — C. setaceum Ehrbg. M. — 0. Kutzingii Breb. 

 St. — C. cor7iu Ehrbg. M. — C. acutum Breb. M., Sc, Se., Reeth. 

 — C. pronum Breb. M. — C. subidatum Kg. S. — C. linea Perty. M. 



Penium margaritaceum Breb. M. — P. cylindrus Breb. M. — P. 

 digitus Breb. Frequent. — P. lamellosum Breb. M. — P. interruptum 

 Breb. M., S. — P. closterioides Ralfs. M., C, Se., Reeth. — P. 

 navicula Breb. M. — P. Brebissonii Ralfs. Common. This was 

 very abundant in a small pool at above 2200 ft. on Great Shunnor 

 Fell. The fig. (3) with parasite was from Mickle Fell. — P. Mooreanum 

 Archer. M. — P. minutissimum Nord. M. — P. cucurbitinum Biss. 

 M. — p. subpolymorphuyn Nord. M. This agrees exactly with the 

 figure and dimensions in Nordstedt's * Fresh-water Algae of New 

 Zealand and Australia,' published in Stockholm, 1888. 



Cylindrocystis diplospora Lund. M., S. — C. crassa D. By. Fre- 

 quent. 



Tetmemorus Brebissonii Ralfs. M., Cotterdale. The abnormal 

 form was from Mickle Fell. — T. lavis Ralfs. M., S., Cotterdale. — 

 T. granulatus Ralfs. Common. 



Micrasterias mucronata Rabh. C. — M. Americana Ralfs. M. — 

 M. Americana Ralfs, a form of var. recta Wolle. M. Fig. 13. — M. 

 denticulata Breb. M., S., Se. — M. roiafa Ralfs. M., C. — M.papil- 

 lifera Breb. C. — M. truncata Breb. St., M. — M, crenata Breb. 

 M., C. 



Euastrum oblongum Grev. C, M. — E. crassum Kg. C, M. — 

 E. affine Ralfs. M. — E. insigne Hass. C, M. — E. didelta Ralfs. 

 C., M. — E, cuneatum Jenner, M, — E. ansatum Ralfs. M. — E. 



U.2 



