MAKINK AM. 15 



to the right and left, aome fifteen secondary similar tilamt-nis each in its sheath of small cells, (x 25.) 

 Fig. 18ft. Part of the HUM, showing an ensbeathed necomlury filament apjwrently conUininf tjlon ; the 

 large cavity on the left is merely u ordinary cell of the ilialltis. (x 450.) Fig. Ha. Longitudinal 

 Motion of mature stem, showing the primary axial tilunicnl with its limnetic* (sMondary MlamrnU) and 

 their anastomoses; all these filaments are distantly articulated, (x 4.) Fig. 14ft. Small portion of 

 longitudinal section of item, showing a secondary filament fuintly indicated within it* sheath of small 

 cells, (x 340.) Fig. 15. Transverse section of an ultimate ramulus showing the primary axial filament 

 in the centre, (x 11".) 



Dttmarutia viridit Lam. var. distant, Hook, and Han-. Fig. 1C. Transverse section of stem, showing 

 a denser medullary tissue in which the primary axial filament hit* Income obliterated, (x 25.) 



Gracilaria dKmmtioidts nob. Fig. 17. Antarctic specimen consisting of numerous cuneato-Iincar 

 proliferations arising from a fragment of an old frond ; natural size. 



PLATE IV. 



Qracilaria dumontioidtt (continued). Fig. 18. Transverse section of the above-mentioned fragment 

 of old frond near its margin, where the cortex becomes thicker and polystroinatic ; the internal tissue 

 consists of Urge cells permanently flattened in drying the plant, (x 400.) Fig. 19. Monostromutic 

 cortex in surface view, (x 650.) Fig. 20. Arctic plant named by Harvey Halonattion dinwintioidei, 

 collected by Dr. Lyall in lat. 7ft" X., and preserved in the British Museum ; it* proliferations are very 

 long and simply linear ; natural size. 



Fhyllopliora antarriiea nob. Fig. 21 a. Plant bearing marginal cystocarps ; natural size. Fig. 21ft. 

 Sterile plant bearing large and small proliferations ; natural size. Fig. ii'. longitudinal section of 

 cystocarpic branch, containing a compound cystocarpic nucleus. ( x 80.) 



Spoiiffoflonium orthocladum sp. nov. Fig. 23. Part of plant; natural size. Fig. 24. Rather 

 diagrammatic representation of apical part of a branch, showing the long, straight, subulate rumellt. 

 (X 35.) Figs. 25o, 25ft. Young procarpia with trichogyne. 



