48 W. MILNE ON THE 



(2) thought C. elegans (Ehr.) was really Adineta. That is prob- 

 'ably a mistake. At any rate I was satisfied that Callidina (Ehr.) 

 could not include the short-footed species, and so I constituted 

 a genus, Macrotrachela, for them. Ehrenberg's genus is not 

 necessarily done away with. 



The definition for Macrotrachela first given still applies, with 

 an addition rendered necessary owing to Mr. Bryce's removal 

 of the pellet-makers into a new genus — a thoroughly sound 

 proceeding — Macrotrachela : — Bdelloida having three toes ; 

 foot shorter than the pre-intestinal part ; oviparous ; and not 

 pellet-makers. 



I shall in this paper, therefore, place all species which answer 

 to this definition under the above genus. 



Harring (12) has taken the same view with regard to the name 

 of the genus. 



The genus Habrotrocha is growing into a very large and un- 

 wieldy group, so I have taken this opportunity to separate some, 

 and place them in a new genus, Otostephanos. They are different 

 from all the others in that they possess a ring of fair thickness 

 round the corona, with short breaks ventrally and dorsally. 

 Murray's H. auriculata (10) which I have known for several years, 

 is one of them. I have three other species to describe. 



In the description of species I generally mention the nature of 

 the lamella. Some writers consider that there are two separate 

 lamellae, at least in some species. I have never been able to 

 make out more than one. There are several undoubted instances 

 of a single hood-like lamella, without any indentation whatever, 

 as in H. cucullata (Murray). The common form has a sharp fold 

 in the middle of the lamella, giving it a double appearance, but 

 not with two separate parts. There are some which seem to me 

 to have a double fold, giving in certain positions a triple lamella, 

 as in P. grandis ; and others with a triple fold giving a quadruple 

 lamella, as in M. russeola and M. Ehrenbergi. The ear processes 

 mentioned by Janson (3) as part of the rostral sheath in the 

 latter, are part of the lamella. 



I have made some general remarks on the jaws of Philodina, 

 which will be found under the description of Monoceros falcatus. 



In 1906 my attention was drawn to a small animal, chiefly 

 through the odd appearance of a bunch of large appendages, 



