58 JAMES MURRAY 



The sixteen species ofRotifera are thus distributed : eight known species, five new 

 species, three not identified. While there are only five new species named, one of the 

 others (Philodina, sp.) though not sufficiently studied to be named, is certainly new, 

 and several of the known species differ more or less from their types, and may be 

 incipient species resulting from long isolation in peculiar conditions. 



Peculiarities. The distinctive characters of the new species are not very remark- 

 able. They consist in the forms and proportions of the spurs, head, upper lip, &c., or in 

 the possession of peculiar processes (Philodina alata). There are no peculiar types. 

 Development has gone on lines similar to those it might have followed in any region. 

 The rotifers may have acquired peculiar physiological properties, enabling them to 

 resist the rigours of the Antarctic climate, but such adaptation (if it has taken place) 

 is not correlated with any peculiarity in outward form. 



Reviewing the rotifer fauna as a whole, its most notable features are the general 

 prevalence of red colour among the Bdelloids, and the viviparous reproduction 

 acquired by some of them belonging to groups which are rarely viviparous. 



Colour of Bdelloids. All the Philodince, except the unnamed species, have the 

 voluminous stomach coloured of a vivid deep crimson. This colour is shared in equal 

 degree by Callidina habita. Callidina constricta and C. angularis have the stomach 

 sometimes red, sometimes brown, and occasionally pale yellow. None of the 

 Adinetce have red stomachs. A. grandis has the alimentary tract of a warm brown 

 colour, the others are pale yellow or colourless. 



The prevalent red colour may be related to the nature of the food. Callidina 

 habita and C. constricta are not normally red in other countries. All the species 

 live among the same plants, which are of a warm orange colour, but associated with 

 this are numerous green and blue-green Algae, so that there is a variety of food 

 available, and the different species may select different foods. We have no exact 

 information as to the kinds of food actually eaten by the Antarctic species. Though 

 they can be readily watched feeding, they rarely swallow organic matter in recognis- 

 able condition, but fine, flocculent material, the result of decomposition. Bdelloids 

 have the power of selecting their food. A pair of knuckle-like processes in the 

 gullet can be brought together, and these are opened or closed according as the 

 particles swept down the funnel are acceptable or not. 



There were no red-coloured rotifers in Green Lake, which was very saline. The 

 only two Bdelloids which occurred there were Adineta grandis and Callidina con- 

 stricta. A. grandis was never red in any lake, but in freshwater lakes C. constricta 

 had sometimes a red stomach. 



Reproduction. Of the Antarctic rotifers seven are oviparous, two are viviparous^ 

 and the reproduction of the remaining seven is unknown. The genus Rotifer, all 

 the members of which are viviparous, is unknown in the region. 



The two viviparous species, Philodina gregaria and Adineta grandis, prepon- 

 derate enormously in numbers over all the other species. This mode of reproduction 



