373 



12. Gelidium unilaterale, H. et B., fronde lineari angusta com- 

 pressa ramosa, ramis arcuatis plerumque secundis patentibus, 

 ramulis secundis horizontalibus obtusis filiformibus. Hab. 

 Tahiti. 



13. Liagora Jiirta H. et B., subcalcarea vage ramosa ; ramis 

 alternis v. oppositls elongatis attenuatis sirnplicibus vel furcatis 

 velutino-hirtis purpureis, ramulis lateralibus paucis filiformibus. 

 Hah. Navigators' Islands. 



14. Caiilerpa falcifolia^ H. et B., caule repente glabro, ramis 

 erectis simplicibus v. furcatis foliosis, foliis densissimis undique 

 insertis imbricatis falcatis compressis mucronatis. Hah. Ton- 

 gataboo. 



15. Caulerpa Pickeringii, H. et B., caule prostrate, spongioso 

 foliis densissime vestito per totam longitudinem radicante, ramis 

 erectis brevibus mammillse-formibus spongiosis foliosis, foliis ver- 

 ticillatis creberrimis horizontalibus pluries dichotomis segmentis 

 fastigiatis apicibusque furcatis vel bimucronulatis. Hah. Wilson's 

 Island, Paumotu Group. 



We have great pleasure in affixing to this remarkable plant 

 the name of Dr. Pickering, who collected many of the Algae 

 here described, and . whose ethnological writings are so well 

 known and appreciated. 



16. Dictyota hidentata^ H. et B., fronde basi vix stuposa cune- 

 ata pluries dichotoma, segmentis sursum latioribus, sinubus rotun- 

 datis, apicibus junioribus acute bidentatis,areolis rectangularibus, 

 soris minutissimis per totam paginam frondis sparsis. Hah. 

 Mindanao. 



Chlokodesmis, Nov. Gen. Siphonearum Vauchericae. Gen. 

 Char. Stipes spongiosus, e filis tenuissimis membranaceis den- 

 sissime intertextis compositus, apice in fila libera penicillata 

 desinens. Fila penicillata membranacea continua dichotoma, 

 libera, ad axillas constricta, pseudo-articulata ; articulis succo 

 viridi repletis. 



17. Chlorodesmis comosa, H, et B., Hah. Feejee Islands. 



A curious plant, with the habit of a Penicillus, but not in the 

 least calcareous. 



