318 RHIZOPHYSA. 



RHIZOPHYSA Peron and Lesdeur, 1807. 



For criticism of Haeckel's genera Cannophysa, Linophj-sa, Aurophj'sa, 

 and Nectophysa, and foi- the reasons which show that they are synonyms of 

 Rhizophysa, I refer the reader to Chun ('97b, p. 77), who also includes Lino- 

 physa Haeckel. Although this genus is not valid, the species for which it is 

 instituted, Rhizophysa conifera Studer ('78) belongs, not to Rhizophysa but to 

 Pterophysa (Schneider, '98, Lens and Van Riemsdijk, :08, p. 106). 



Apart from conifera, Chun ('97b, p. 104) recognized the following species in 

 the compound genus Rhizophysa: — R. filiformis Forskal, R. eysenhardtii Gegen- 

 baur, R. clavigera Chun (= Cannophysa filiformis Mayer), R. gracilis Fewkes, 

 and R. murrayana Haeckel. But Fewkes's account of R. gracilis and Haeckel's 

 description and beautiful figures of R. {Cannophysa) murrayana agree so well 

 with R. filiformis, especially in the form of the tentilla, that I follow Schneider, 

 and Lens and Van Riemsdijk in uniting them with the latter. WTiether R. 

 clavigera is reallj^ a distinct species can hardly be determined from Mayer's very 

 confused account, or from his figure which was evidently drawn from a fragmen- 

 tary specimen. My opinion is that it was probably R. filiformis, with siphons 

 and tentacles twisted together. Schneider includes in this genus the R. uvaria 

 of Fewkes, but this form has polygastric cormidia, and therefore belongs to 

 Salacia (Haeckel and Chun). 



Lens and Van Riemsdijk, after examining the literature of the genus, came 

 to the conclusion, with which I entirely agree, that only two species, filiformis 

 and eysenhardtii, are valid. These are distinguished from each other by the 

 presence in the former of three kinds of tentilla, tricornuate, dendritic, and 

 "vogelkopfahnlich," and in the latter of simple filiform tentilla only. 



Schneider ('98) used the name R. mertensi Brandt to replace eysenhardtii 

 Gegenbaur, evidently supposing that Brandt's ('35, p. 33) description of the 

 tentilla as "Tentacula composita ramulis, i. e. tentaculis porpriis, simplicibus" 

 meant that they were filiform. But Haeckel ('88b, p. 329) who examined Mer- 

 ten's unpublished figures of this species expressly states that it "exhibits distinctly 

 two different kinds of branched tentilla." Unfortunately I have not been able 

 to verify this statement; but under the circumstances there seems to be only 

 one course open, namely, to consider mertensi a synonym of filiformis, on the 

 strength of its having two kinds of tentilla, and to retain the name eysenhardtii, 

 as is done by Lens and Van Riemsdijk, for the species with filiform tentilla. 



The name filiformis Forskal is now universally used for the form with 



