ALG^ FEOM THE WEST INDIES. 279 



60. "N A.Tic\jLA bo^eaJjIS, Kttetz. [Piauulariaborealis,^7?re;2&., 

 TF. S?n. Brit. Dial. ii. p. 94; Bahh. Fl. Earop. Alg. i. p. 216.] 



Hah. "With tbe preceding species. 



61. N. MESOLEPTA, EJirenb. [Pinnularia mesolepta, W. Sm. 

 Brit. Diat. i. p. 58, t. 19. f. 182.] 



Hah. On bed of stream in crater of Grande Soufriere, Dominica. 

 jS'o. 881. 



62. FfitrsTULiA EHOMBOiDEs, D(9 Toui. {SyllogeAlgar. vol. ii. 

 p. 227.) [Navicnla rhomboides, Ehrenh., W. Sm. Brit, Diat. i. 

 p. 46, t. 16. f. 129.] 



Hah. In stream, crater of Grande Soufriere. No. 908. 



Yar. SAXONic.v, De Toni. (Z. c.) [Frustulia saxonica, Bahh. 

 Navicula crassinervia, Breh. in JV. Sm. Brit. Diat. i. p. 47, 

 t. .31. f. 271.] 



Hah. In streams (cold, warm, and hot), crater of Grande 

 Soufriere, Domiuica. Nos. 883 and 908. Also amongst mosses 

 on trees, summit of Trois Pitons (4500 ft.), Dominica. IS'os. 

 903 and 904. 



63. GoMPHOXEMA. TENELLUM, Kuetz. {W. Sm. Brit. Diat. i. 

 p. 80, t. 29. f. 243.) 



Hah. On damp wall of dam. Sharp's Eiver, St. Yincent. 

 No. 477. 



EXPLANATION OF THE PLATES. 



Plate XIIL 



Figs. 1-4. Zygneina ( Zygogonium) pachydermum, n. sp. Conjugated spe- 

 cimens, 520/1. 

 5-8. Ditto. Four zygospores, 520/1. 

 9, 10. Ditto. Two specimens, with azygospores, 520/1. 

 11-15. Ditto, sterile filaments; fig. 11, 520/1; figs. 12-15, filaments, 

 showing short branches, 120/1. 

 Fig. 16. Ditto, showing conjugation between three filaments, 120/1. 

 Fig. 17. Cosmarium ohliquum, Nordst., f. minor, Nordst., 520/1. 



Plate XIY, 



Figs. 1-6. Zygnemapachydermum,T^.s^.,ydir-.confervoides,^.\Kr. Figs. 1&2, 

 filaments without cell-contents ; fig. 3, filament with contents 

 delineated ; fig. 4, attempt at conjugation ? ; fig. 5, cells showing 

 longitudinal division. Figs. 1-5, .520/1 ; fig. 6, 830/1. 

 7-11. MicrochcBte tenuissirna, n. sp. 520/1. 

 12-15. Scyt&iiema javaniciim, Bornet. 520/1. 



