AND ITS ALLIES. 211 



of the long-spurred species which live well in stagnant water. 

 Several of his drawings show the deep constrictions which 

 characterise Rotifer tardus, R. trisecatus, R. longirostris, and 

 Philodina macrostyla, and hardly any other species. He correctly 

 discriminates the rostrum and the antenna (which Giglioli as 

 late as 1863 (9) failed to do) when both were displayed together. 



The lobed termination of what he calls the "trornpe" or 

 rostrum in figure A is suggestive of the antenna of P. macrostyla, 

 and the more slender trornpe at letter It is strikingly like the 

 antenna in a position it sometimes assumes. The rostrum proper 

 never looks like that, and I think we are justified in identifying 

 that figure (Plate 11, S, K, T) as P. macrostyla. He might 

 readily confuse the antenna with the rostrum when both were 

 not extended together. For his descriptions of the "chenille 

 aquatique " see (14) part 2, p. 80. 



Ehrenberg (7), in the year 1831, in his second classification, 

 describes three additional species of Philodina and gives a short 

 description of P. aculeata. 



It was not until 1838 (8) in the Infusionsthierchen that he 

 described the second species of our group, P. macrostyla. 



Gosse, in 1886 (11), described his P. tuberculata apparently 

 unaware of Ehrenberg's P. macrostyla, as no comparison is made 

 of the two species. Hudson (1889) in the Supplement to The 

 Rotifera withdrew Gosse's tuberculata, on the strength of Gosse's 

 own notes and the experience of other observers with tuberculata 

 (Western, 19). 



The last species of the group, P. spinosa, was described by 

 Bryce (1) as Callidina spinosa in 1892. 



The two earlier described species, P. aculeata and P. macrostyla, 

 have been much written about, the former especially giving rise 

 to great divergence of opinion, much of which was gratuitous, 

 as the species really varies in different localities. 



In 1893 Janson (13) described a variety medio -aculeata of 

 P. acideata. 



So far as I am aware, no other form of the group has received 

 a name, either as variety or species, though some other names of 

 alleged species are believed to be synonymous for P. macrostyla. 



