196 



On Two New Species of Macrotrachelous Callidin^. 

 By David Brtce. 



{Read January 20th, 1893.) 



(Plate XT.) 



Before entering upon the description of the new forms, I take 

 this opportunity of referring to two points as to which some 

 misconception may exist. The first arises in part from an error 

 of my own. In my former paper on the group of Macrotrache- 

 lous Callidinae I mentioned a species, which is not uncommon, 

 as " the form described by Mr. Milne as the Callidina elegans of 

 Ehrenberg." T should have referred to it simply as the Macro- 

 trachela elegans of Milne, for, in point of fact, that author, as I 

 have more recently stated, had come to the conclusion that 

 Ehrenberg's genus Callidina represented Philodinasa, having 

 that type of corona which we now recognize as distinctive of 

 the genus Adineta. It follows from this that his two species, 

 M. elegans and M. hidens, were believed by him to be distinct 

 from the two species of Callidina described previously under 

 the same specific names. Yet Dr. Hudson, regarding all the 

 Macro trachelas of Milne as so many species of Callidina 

 (Rotif. Supp., p. 59), proceeds (Index, ibid., p. 64) to refer 

 M. elegans to the Callidina elegans of Ehrenberg, and M . hidens 

 to the Callidina hidens of Gosse, being obviously misled by Mr. 

 Milne's unfortunate choice of names Having compared the 

 descriptions given in " The Rotifera " (i., p. 109) with those 

 furnished by Mr. Milne, and having found forms agreeing with 

 both of the latter, I have little doubt that all four species are 

 distinct, and T would suggest that Mr. Milne should remove the 

 present block by bestowing new names upon his forms. I ven- 

 ture to add, as my own opinion, that the fact that a specific 

 name has been already employed should be a supreme objection 

 to its use for a new form of any conceivable propinquity of 



