Vol. Ill, No. 2.] Notes on the Freshwater Fauna of India 87 



Statoblasts on firmer supports often of two forms (on leaves gener- 

 ally onlj of one). Floating statoHast roundish oval, medallion- 

 shaped, 0-214 to 0-53 mm. long and 0-2 to 0-4 13 mm. broad ; relative 

 proportions of breadth and length as 1 to 1— as 10 to 1-5 ; the 

 sessile form often with reticulated markings on its margin, not 



fundamentally 



»> 



{ihid., p. 122.) 



The form described by the same author under the name of 

 Plumatella phzUppmensis is diagnosed as follows : — " Colony 

 branched like a stag's antlers, only -with horizontal creeping 

 branches, very stout. The ramifications frequently afford a character- 

 istic representation of a " Dichasium," inasmuch as the main axis 

 apparently ends in seven short unbranched little tubes between 

 two approximately equal stout lateral axes. Tubes almost uni- 

 form, dark reddish brown (generally even the youngest), some- 

 what burnished, not encrusted, strongly keeled, but with the 

 region round the aperture not hyaline. This region level (inspirit 

 specimens), closing the aperture like the lid of a box. Statoblasts 

 which are provided with a ring of air-cells resembling those of 

 P- emarginata, of a deep brown colour; length 0'4 to 0*471 mm., 

 breadth t)"2 to 0'255 mm. Relative proportions of breadth and 

 length as 1 to 1*7 — as 1 to 2'07, Number of tentacles uncertain. 

 Fundus of the stomach conical, tapering to a point." (ibtd.^ p. 118, 

 n ote. ) 



P. punctata is easily distinguished from any of the above by 

 its thickened hyaline ectocyst, which causes it to resemble ZophO" 

 pus to some extent. The forms (punctata, Hancock ; vesicularisy 

 Leidy ; vttrea, Hyatt, and copJii/dea, Kafka) included in this spe- 

 cies by Kraepelin appear to be synonymous, P. vesicularis and 

 P. vitrea constitute JuUien's genus Hyaltnella^ which is unnecessary. 

 The diagnosis of P* philippinensis is clear enough ; but those 

 of P. princeps and P. polyTnorpha are so full of qualifying words 

 that they are useless in tlie determination of specimens. Granted 

 that Plumatella punctata and P. philippinensis are distinct species, 

 only two courses seem at all permissable as regards the remainder 

 of the forms which have been described in the genus and in 

 Alcyonella, viz., either to regard them for the present as one ex- 

 tremely variable species with a number of more or less constant 

 subspecies and varieties, and liable to undergo a number of tempo- 

 rary chano^es owing to the effect of environment on the^ individual 

 colony ; or to treat every adequately described form which has not 

 actually been proved to be a temporary phase as a distinct species. 

 Even granted that Kraepelin's diagnoses of his ^ two species are 

 sufficiently exact, it does not seem legitimate (especially when well- 

 known names are concerned) to give nev> names to previously de- 



forms, however ereat the confusion 



recognizable descript 



rae 



cep^ as cc 

 Tnorpha as 



ynomony. Moreover, he refers to Mis i . prtn- 

 >f the " Emarginata-Eeihe *' and to his P. poly- 

 r of the " BepenS'Beihe"* of the genus. So far 



