118 CEYLON MARINE BIOLOGICAL REPORTS. 



species reaches as much as 2 mm. in breadth (exclusive of pinnules, of course) and is evidently fiat, with 

 two-sided pinnules. 



That the plant I have reproduced here from Ceylon (fig. 11), collected by Hobnbll on the pearl- 

 banks in the Gulf of Mannar, is identical with Greville's fissidentoides (see Greville, PI. II., loc. cit.) 

 seems to me to be beyond any shadow of doubt. Greville's figure has the main axis in certain parts 

 almost 2 mm. in breadth, and in my figure (drawn natural size from formaUn material) the main axis 

 in many places is fully 2 mm. Also the circumstance thatC. fissidentoides, Grev., has been collected on 

 " the shores of tlie Peninsula of India " supports to some extent the assumption that these plants are quite 

 identical. But, on the other hand, this species is, according to Weber v. Bosse — who had an oppor- 

 tunity of examining the type specimens — synonymous with C. Lessonii. Curiously enough J. G. Agardh 

 does not mention — as far as I have been able to find — anything about Grevtlle'.s C. fissidentoides. 



If, now, it is quite evident that the alga from the pearl banks is identical with Greville's G. fissi- 

 dentoides and therefore also with Bory's C. Lessonii, on the other hand the matter is by no means equally 

 evident as far as another alga hereunto belonging is concerned, which has been collected by Ferguson 

 at Tuticorin in S. India and numbered 413 in his " Ceylon Algse." It has been determined by Grunow 

 as C. Lessonii — on the label in the Peradeniya Herbarium one reads " C. pectinata, Kutz " — and it is 

 presumably the very same alga as Murray calls G. fissidentoides in his •• Catalogue of Ceylon Algae, " p. 37. 

 Weber v. Bosse, on the other hand, will not accept this determination (cf. " Monographic ," pp. 339, 340) 

 but is of the opinion that Ferguson's Ceylon Algae No. 413 is to be referred rather to G. plumulifera, Zan- 

 ARDiNi (= G. pennata, J. G. Agardh) , at the same time as the author questions whether G. plumulifera is not 

 possibly to be coupled with G. Lessonii, a matter which can only be settled when fresh specimens have 

 been examined. In the Algal Herbarium in Peradeniya, which was kindly placed at my disposal, there 

 are several specimens of this Ferguson's Ceylon Alga 413, but also another one too (Ferguson, C. A. 161) 

 labelled "C. fissidentoides," though of the last-named there is only one very poor specimen, only a few 

 indeterminable fragments. 



Where do these forms belong ? The first named (C. A. 413) fanly corresponds in the main with 

 Weber v. Bosse' s description and figure of Gaulerpa plumulifera, Zanardini {loc. cit. p. 340, PI. 

 XXXI., fig. 3). It is, then, distinguished by assimilators with fairly long cylindrical petioles and with 

 many branches (fig. 12). For the rest, the greater part of the branches also look as in Weber v. Bosse's 

 figure (loc. cit. PI. XXI. fig. 3), which seems to justify tliis form being referred to G. plumulifera. But on 

 a closer examination of the Peradeniya specimens it is soon clear that some are characterized by branches 

 of a quite different kind, viz. , partly broad, coarse ones, which by their size and breadth are sharply distinct 

 from the others (the transitions to which are also very abrupt), and partly weak cylindrical ones with 

 three-sided pinnules. 



Fig. 12 shows specimens of Ferguson's C.A. 413. It is remarkable how the great broad branches 

 absolutely correspond with the cliaracter which has been pouited out as characteristic for Lessonii. i.e. 

 the relative breadth of tlie a.xis (up to and above 2 m.m.)and the length of the pinnules. A comparison 

 between these branches and G. Lessonii in fig. 11 shows, therefore, a perfect correspondence. But from 

 this it is also the more explicable how Grcjnow has been able to call this Alga G. Lessonii, and how Mur- 

 ray has included G. fissidentoides in liis Catalogue of Ceylon Algae. On the other hand, these broad 

 branches are not found in all specimens — e.g. not in Ferguson's specimens in Agardh's Herbarium (Nos. 

 16614, 16615) — and pi'obably were not in the material that Weber v. Bosse had an opportunity of exam- 

 ining — they are not figured in her monograph PI. XXXI., fig. 3 — and from this it is quite natural that she 

 should not have combined this species with Lessonii, but rather with G. plumulifera, Zanardini. But 

 the appearance of the broad branches in tlie Peradeniya specimens shows, on the other hand, that one is 

 justified in combining it with Lessonii, granting it to be a special form, characterized — as so many other 

 Gaulerpa forms — by some branches showing an appearance that corresponds with one species, other 

 blanches with another. As far as the third kind of branches is concerned, they have an appearance that 



