270 On Clathrulina elegans. 



the common monads for them led the observer to abandon the 

 search. Returning to the parent capsule, a third monad was 

 found to have escaped in the meantime. After twenty-four 

 minutes' quiescence, the fourth body in its turn approached 

 the wall of the capsule, emerged, developed a flagellum, and 

 swam away, a free monad. With a one-half inch objective 

 this one was closely watched, and the following details noted : 

 — body oval, transparent ; nucleus present, dark-coloured and 

 situated near the centre; a pulsating pink vesicle, situated 

 posteriorly ; and a flagellum slightly longer than the body. 



For one hour and fifty-eight minutes the monad swam in 

 all directions, usually in concentric, ever-widening circles, 

 then suddenly darting oif at a tangent to begin again in a 

 new spot. At the end of this time, in its course it touched 

 one of the free young ClathruUnce^ and, to prevent it being 

 used as food by its cannibal relation, the glass cover of the 

 live-box was tapped, so that the current produced carried the 

 monad a short distance away, where it remained almost 

 motionless several seconds. 



By a change to a power of 350 diameters, the monad was 

 shown to attach the top of its flagellum to the glass and re- 

 volve swiftly for a few moments, when instantly the whole 

 body became spherical, rays were shot out, and the trans- 

 formed monad was in no point, except that of size, to be dis- 

 tinguished from its Actinophrys-\\kQ cousin, whose career had 

 been so difierent. In some cases the monads remained at- 

 tached by the flagellum, using it as a pedicel. The whole 

 development, from the time when the monad began its free 

 Hfe, occupied two hours and some seconds. 



This mode of reproduction secures a more widespread dis- 

 tribution of the young than would be possible did this depend 

 on the sluggish Actinoi)lirys form. It seems reasonable to 

 suppose that this is a wise provision for the perpetuation of 

 the species, should adverse conditions of life arise ; and also 

 to prevent an undue accumulation of the animals within a 

 circumscribed space. 



The tendency of these E,hizopods to attach themselves to 

 the parent capsule (a result of the inertness of the Actino- 

 phrys form of young) , together with the fact that this mode of 

 reproduction was apparently induced by a lengthened captivity 

 (necessarily the source of adverse conditions), would point to 

 the reasonableness of the above conclusions. 



