132 



ME. E. M. HOLMES OS CODIOLUM GBEGABIUM. 



Navicula major, Kuetz. 

 N. gibba, Ehrenb. 

 Stauroneis linearis, W. Sm. 

 Synedra vitrea, Kuetz. 

 S. obtusa, W. Sm. 

 S. biceps, W. Sm. 

 Nitzschia panduriformis, Greg. 

 Stauroneis anceps, W. Sm. 

 Himantidium gracile, Grunow. 

 Ceratoneis alpina, Grunow. 

 Near Montealegre in Lago 

 Paxusara. 

 Navicula gibba, Ehrenb. 

 N. Brebissonii, Kuetz. 

 N. rhyncocephala, Kuetz. 

 N. acuta, W. Sm. 

 Synedra biceps, Kuetz. 

 Himantidium gracile, Grunow. 

 On leaves of Polygonum, Rio 

 Troinbetas. 

 Several forms of Eunotia. 

 Navicula rhomboides, Ehrenb. 

 N. Bacillum, Ehrenb. 



Navicula gracillima, Pritchard. 



N. ovalis, W. Sm. 



N. exigua, Greg. 



N. dirynchus, Ehrenb. 



N. americana, Ehrenb. 



Desmogonium guianense, Ehrenb. 



Actinella mirabilis, Grunow. 



Synedra biceps, Kuetz. 



S. ulna, Ehrenb. 



Stauroneis anceps, Ehrenb. 



Nitzschia thermalis, Awd. 



Cymbella scotica, Kuetz. 



C. turgida, Greg. 



Gomphonema lanceolatum, 



Ehrenb. 

 G. turris, Ehrenb. 

 G. vibrio, Ehrenb. 

 G. hebridense, Greg. ? 

 Amphora delphinia, Bailey. 

 Surirella linearis, Ehrenb. 

 S. demerarae, Ehrenb. 

 S. arcta, Schmidt. 



On Codiolum gregarium, A. Braun. 

 By Edwaed Moeell HolMes, F.L.S. 

 [Read March 4, 1880.] 

 This interesting addition to the British marine flora was dis- 

 covered at Teignmouth, in November 1855, by the Bev. B. Cress- 

 well, but not identified until the close of last year, when speci- 

 mens were sent to Dr. Bornet and recognized by him. Compa- 

 ratively few algologists in this country have paid attention to the 

 minute alga) which grow near high-water mark, to which Mr. 

 Cresswell has almost exclusively directed his investigations. For 

 this reason he has not only met with many species overlooked by 

 other algologists, but has been the fortunate discoverer of the 

 curious Schizotlirix Cresswellii, and of the somewhat anomalous 

 plant which forms the subject of the present communication, and 

 which has now, for the first time, been recorded as a British alga. 

 Codiolum gregarium was first discovered in 1852 by A. Braun in 

 Heligoland, growing on posts and woodwork near the sea, and 



