ADINETAD/E. HfJ 



vesicle was also plainly visible : Mr. Davis says that its period is about twenty seconds in 

 tlie young, and from two minutes to five minutes in the adult. By compression 1 obtained 

 an unusually distinct view of the lateral canals (fig. 106), which showed clear against the 

 grey ground of the ovary. Mr. Davis has seen five vibratile tags on each side, but not the 

 lateral canals ; and I succeeded in finding two pairs of tags attached to the canals : one pair 

 just below the transverse ridges of the corona's base, and another mid-way between tbis 

 point and the contractile vesicle. There is a dorsal antenna; but no eyes: thu nervous 

 ganglion has not been made Out. 



A. vaga may be recognised at once by its peculiar movements, wliicli are unlike 

 those of any other Rotiferon I am ac(iuainted with, and are also extremely embarrassing 

 to the observer. It fastens itself by its foot, extends its body to its full length, and 

 then swiftly contracts itself. Nor is this all ; for, instantly extending itself again, it 

 alters its direction, as well as its distance from the surface to which it is attached. In 

 this way it will work around its toes, as around a pivot, compelling the observer to make 

 mcessant alterations of the stage and focus. In fact very little is to be learned of its 

 structure, while it is permitted to go free. When imprisoned in a very closely flattened 

 drop of water, it is a little more manageable, for it ceases then to dart backwards and 

 forwards ; but on the other hand it makes up for tliis by constantly gliding about at a 

 very fair pace. It is quite incapable of swimming in the open, and may now and then 

 be seen rolUng ignominiously from the top of the glass cell to the bottom ; but it glides 

 with ease over the surfaces of stems, plants, or glass, by the reaction of those sur- 

 faces on the ciliated head. It is, if possible, a hardier creature even than Philo- 

 dina roseola ; for Lord Osborne tells me that he has repeatedly found that, in a mixed 

 gathering of the two, A. vaga will survive successive dryings and moistenings which 

 have proved fatal to all the former.' 



Length. From ^'ij to t;V inch. Habitat. In some stone garden-vases at Bland- 

 ford (Lord S. G. Osborne) ; in a mill-pond at Petit Bot, Guernsey (C.T.H.) ; frequently 

 in dried gatheriiigs oi Philodina roseola. 



' Mr. Davis's experiments (loc. cit.) show tliat tliis is not always the case. 



