ri.OSTKKll M. IS] 



Length 221-2: 7 58 / u; breadth 10-10-5^; l.tvadth of 

 apices 1'7/x; length of zygosp. 57'5/x.; breadth of 

 zygosp. L'S-7/x. 



ENGLAND. Wickeii Feu, Cambridge ! 



This species is proportionately shorter than Cl. pronnni 

 l'>ivl>., the ;i])iees berni^ lunch less produced and truncate. It 

 is somewhat larger than ('/. tn-utmii (Lyn,u'l>.) llrel)., and its 

 apices are quite different. The zyg'ospore is also peculiar. 



54. Closterium lineatum Ehrenb. 

 (PI. XXIV, figs. 1-5.) 



Cloxlfi-iinii Inn 'ilium Ehrenb. 1834; Infus. 1838, p. 96, t. 6, f. viii ; Mem-gh. 

 Synops. Desm. INK), p. 234; Mass. Brit. Freshw. Alg. 1843, p. 37-', t. 8S, 

 f. 1 ; Kali's, Brit, Desm. is is. p. 173, t. 30, f. 1 ; Arch, iu Pi-itch. Infus. 

 1861, p. 749, t. 3, f. 41 , 1-2 ; h'abenli. Flor. Europ. Algar. Ill, 1868, p. 130 ; 

 Lund. Desm. Suec. 1871, p. 79; Delp Desm. Subalp. 1877, p. 117, t. 17, 

 f. 28-30; Kirchn. Alg. Schles. 1878, p. 139; Wolle, Desm. U.S. 188 1, 

 p. 43, t, 0, f. 10; Cooke, Brit, Desm. 1880, p. 31, t. 12, f. 1, t. 15, f. 3; 

 Hans--. Prudr. Al-viin. Bi.lnn. 1888, p. 180; De Toni, Syll. Aly. 18S9. 

 p. 838 ; West, Alg. W. Ireland, 1892, p. 124 ; Lutkem. Desm. Atters.-.-s, 

 1893, p. 543; Roy & Biss. Scott. Desm. 1894, p. 240; Nurdst. Ind.-x 

 Desm. 1890, p. 158 : West A; (A. S. West, Ali^. S. England, 1897, p. 4S2 ; 

 G. S. West, Alora-fl. Cambr. 1899, p. 113; West & G. S. West, Al^a-tt. 

 Yorks. 1900, p. 55 ; Alg. N. Ireland, 1902, p. 24; Scott. Freshw. Plankton, 

 I, 1903, p. 525. 



Arthroilin liin'uta Kuntze, Kevis. gen. plant. 1891, p. 883. 



Closterium didymocarpu/m Schmidle, Alg\ ans Nyassa-See, 1903, p. 65, 1. 1, 

 f. 15, 21. 



Cells large, long and narrow, 16-24 times longer 

 than their diameter, moderately curved, median portion 

 of the cell fairly straight and cylindrical, inner margin 

 faintly and Avidely tumid, moderately curved and 

 gradually attenuated towards the apices, which are 

 broad and truncatelv rounded ; cell-wall striated, stri;e 



/ 



rather variable, from 10 to 20 visible across the cell, 

 yellow-brown or reddish-brown in colour; chloroplasts 

 with about six ridges and a median ro\v of nine to 

 eleven pyrenoids ; terminal vacuole with a close cluster 

 of several moving granules. 



Zygospore double; each part ovoid or ovoid-ellip- 

 soid, with thick, smooth walls. 



Length 415-7<)0/x; breadth 17-35 //,; breadtli of 

 apices 7-10//,; diam. of zygosp. 44-08' 5 /x. 



