172 welwitsch's African freshwater alg^. 



I never saw camels browsing on vegetation known or reasonably 

 supposed to be harmful ; my early fears in respect of some, such as 

 the Loranthi and Alyxia huxifolia, having proved quite groundless. 

 Is it not possible that this may have been because there was always 

 some more or less wholesome food within their reach ? The idea is 

 that the camel, so long as it can find a sufficiency of wholesome 

 forage, will not turn to poison, but, should poison-plant largely 

 monopolize a district, the animal will browse upon it, and frequently 

 with fatal results. This idea is backed by information given me 

 showing that, where poison-plant exerts its baleful effects, it occurs 

 in large quantities. 



It should be added that type-specimens of the species described 

 in this paper, as well as the other fodder-plants, are in the Botanical 

 Department of the British Museum. 



PS. — Since writing the above, I find a second Myoporinea 

 noted as a camel fodder-plant. This is — 



75. EremophiJa maculata F. Muell. var. hrevifolia. Between 

 Coolgardie and Broad Arrow ; also between the latter place and 

 Uladdie soak, March. 



WELWITSCH'S AFEICAN FKESHWATER ALG^.. 

 By W. West, F.L.S., and G. S. West, A.R.C.S. 



(Plates 365-369.) 

 (Continued from p. 122.) 



50. C. callistum, sp. u. (tab. 367, fig. 13). C. submediocre, 

 circiter 1^-plo longius quam latins, profunde constrictum, siuu 

 sublineari paullo aperto ; semicellulas pyramido-trapeziformes, an- 

 gulis inferioribus subrectangularibus, angulis superioribus paullo 

 rotundatis, apicibus leviter convexis et glabris, lateribus leviter 

 convexis cvim granulis acutis circiter 8 utrobique, etiam seriebus 

 irregularibus duabus granulorum acutorum intra latus unum- 

 quemque efc serie singula infra apicem, in centro granulis majori- 

 bus circ. 15 quincuncialiter ordinatis, puuctulis 6 circa granulum 

 unumquemque ; a vertice viste elliptic^e, levissime inflatte in medio 

 utrobique ; a latere visfe subglobosse. Long. 47 /x ; lat. 34 /x ; lat. 

 isthm. 16 jJL ; crass. 20 /x. 



Pungo Andongo. In stagnis prope Anbilla (Condo) ; March 

 1857. No. 177. 



51. C. colonophorum, sp. n. (tab. 367, fig. 1). C. mediocre, 

 paullo latius quam longius, profunde constrictum, sinu angusto- 

 lineari extremo subampliato ; semicellulfe semicirculares apicibus 

 truncatis, verruca magna conica ad angulum inferiorem et superi- 

 orem unumquemque, verrucis brevioribus conicis 4 ad latus unum- 

 quemque, verrucis obtuse conicis 3 intra marginem utrobique et 

 verrucis 4 intra apicem, verruca simili supra medium sinus utro- 

 bique, serie transversa verrucarum majorum 4 trans medium 



