232 MESSES. W. WEST AXD G. S. WEST ON 



each other. AYolle's imperfect figure and description have evidently led E/aciborski (I. c.) 

 to describe the plant as a new species. 



Gemis Onychonema, G. C. Wallich. 



7. O. LJ=VE, Nordst. in A^idensk. Meddel. 1869 (1870), p. 206, t. 3. fig. 34. 



Var. MicnACAOTHUM, Nordst. Alg. et Char. i. p. 3. (Pi. XII. figs. 15-17.) Zygosporse 

 globosae, spinis validis simplicibus nnmerosis brevibus obsessge. 



Diam. zygosp. sine spin. 17-20 /a, cnm spin. 21-26 /u. 



The var. micracanthum appears to be much more abundant than the typical plant. 

 An abnormal form was seen with an oblong-elliptic portion between the two semicells of 

 each cell ; this was slightly larger than the semicells, but of about the same breadth. It 

 was present in all the cells of a long filament, and appears to have resulted from the 

 abnormal development during division of what should have produced two young semi- 

 cells. AYe have also seen this abnormal form in 0. filiforme. Similar cases occur not 

 unfrequently in Staurastnmi and Cosmaritfm, especially in the latter. 



Var. LATUM, nov. var. (PI. XII. fig. 18.) Var. cellulis cotnpressis, latioribus et suban- 

 gularibus,apicibus pro parte tertia apicis uniuscujusque levissime elevatis et trnncatis ; 

 a vertice visis angustioribus, lateribus subrectis ; membrana punctata. 

 Long. 15-15-5 ^x; lat. sine spin. 28 5-30*5^, cum spin. 36-5^: lat. isthm. 3-8-4'6 m ; 

 crass. 7 At. 



Genus Hyalotheca, Kuetz. 



8. H. TJXDULATA, Nordst. in Wittr. & Nordst. Alg. Exsic. no. 248. 

 Long. cell. 10-15 tx ; lat. 6-7 n ; lat. isthm. 4*6-5 ^. 



This characteristic species was met with frequently. It cannot possibly be confounded 

 with Sph(Erozosma excavatum as stated by Wolle (Desm. U.S. p. 24). The diameter of 

 our examples is the same as that of the original Swedish plant and also of British 

 specimens ; Wolle says 9-12 /t (his figure is 14 ^u !). 



Genus Gymnozyga, Ehrenb. 



9. G. MONILIFORMIS, Ehrenb. {Bambusina Brehissonii, Kuetz. ; Bidymoprmm Borreri, 



Ralfs.) 



Var. GEACiLESCENS, Nordst. in Wittr. & Nordst. Alg. Exsic. no. 367. 



Long, zygosp. 21-23^; lat. zygosp. 16-17 /t. (PL XII. fig. 19.) 



This has been found with zygospores by Nordstedt (in Wittr. & Nordst. Alg. Exsic. 



no. 554) from Brazil and by Wolle (Alg. U.S. p. 21, pi. 59. figs. 13, 14) from Elorida. 



We give a figure of a few of the zygospores observed by us. 



10. G. conferyacea, nov. sp. (PL XII. figs. 20, 21.) G, cellulis subrectangularibus, 



l§-2-plo longioribus quam latioribus, leviter latioribus ad medium, annulo singulo 

 delicatissimo mediano ; membrana glabra. 

 Long. 12-18-5 /a ; lat. 9-105 m ; lat. med. 105-12 ^u. 



This has shorter and stouter cells than G. delicatissima, Lagerh., and has only a single 

 median delicate band. 



