210 J. MURRAY ON PHILODINA MACROSTYLA, EHR., 



differs more or less from the rest of the genus. Eye-spots 

 are present or absent. The species are P. aculeata, P. macrostyla, 

 and P. spinosa. It is with this fifth group, the viviparous, long- 

 spurred Philodliute, that we have here to do. 



P. parasitica, Marchoux, is so vaguely described that it is 

 impossible to tell in which group it should be placed, and 

 unfortunately the author gives no figure. 



The species appears to be distinct, but the name has been 

 previously used by Giglioli (9). 



VIVIPAROUS PHILODINAE. 



Macrostyla Group. 



The species of the genus Philodina are oviparous, with four 

 exceptions. The three species of the macrostyla group are 

 very closely related. The fourth species, P. laticornis, has 

 siothing in common with the others, except the mode of repro- 

 duction and the possession of four toes. 



The group is so distinct from the rest of the genus that I 

 would consider it of generic value, but as the whole order 

 Bdelloida requires revision it would be inadvisable to form a 

 new genus till the group is dealt with. 



Historical Sketch. 



In 1830 (6) Ehrenberg, after defining the genus Philodina, 

 and naming the first species P. erythrophthalma, named, without 

 describing, P. aculeata, which is the first notice of any species 

 of the group under consideration. 



Though it was only then that any of our species received 

 a name, I think it likely that one of them had been previously 

 observed and figured. 



Joblot, in 1718 (14), despite his bizarre nomenclature, gives 

 some spirited drawings of Rotifers, which indicate an un- 

 commonly good observer. Some of his species (as Brachionus 

 pala, for instance) can be readily identified. 



The plate of Bdelloids (Plate 11) represents only species with 

 long spurs. Though Joblot supposed that his "aquatic cater- 

 pillars," of which he saw seven or eight, were all of one kind, it 

 is highly probable that in an old infusion there might be several 



