Royal Microscopical Society. 205 



prepared specimens like these, with observations in the life, go to 

 show that the rami, by a rolling motion (actuated by muscles), 

 cause one of the many movements of the apparatus, that of open- 

 ing and closing — scissors-fashion — the teeth-plates ; while the sur- 

 face-contact and pressure-together of the latter are effected by the 

 direct action of the muscular cushions on which they rest. 



This branch of the subject may be concluded by a short history 

 of the life, manners, and vicissitudes of the little collection of C. vaga 

 I now exhibit [a 3 x 1 glass slip with a central cell holding about 

 ten drops of water.] It is a colony of modest virgins ; eager eyes 

 have been on (and off) them for nearly six years anxious to detect 

 instances of feminine frailty, but in vain. They literally scrape up 

 a living thus : keeping the toes attached to the glass, one crawls 

 swiftly straight forward, partly by greater and greater extension of 

 the body, and partly by the action of the ciliated discs, and all the 

 time feeding as it goes ; having attained its greatest extension, the 

 animal suddenly retracts, reducing its length more than half, and 

 without releasing its foothold, turns slightly in another direction, 

 again extends, and again retracts. At last it may have grazed over 

 a circular plane of a diameter double the greatest length of its 

 body ; it then starts for pastures new, generally by crawling some- 

 what in the manner of B. vulgaris. But it travels most quickly 

 when it releases its foothold, contracts some of its posterior joints, 

 and glides on by its cilia only (Fig. 2). Its attempts at swimming 

 are always failures ; one may cast itself from the cover of a tank 

 and wriggle helplessly, as an earth-worm might, until it reaches 

 the bottom ; or it may attach itself to a passing free-swimming 

 philodine, and ride safely to shore. 



Originally this tank contained two species, but one, after keep- 

 ing apart in groups, finally died out. In a larger tank the reverse 

 was the result, the Callidinse dying off and leaving the Philodinaj 

 flourishing. In this fact a careless observer might readily imagine 

 a transmutation of form — one species changing into the other. 

 Much greater changes than these Dr. Bastian supposes he 

 witnessed, such as spores of Algae developing into highly-organized 

 rotifers,* but to say little of my own rather lengthened experience, 

 winch points directly against Dr. Bastian's belief, I could, were 

 permission given, state the adverse opinions of gentlemen whose 

 studies of Botifera extend over as many years as Dr. Bastian's over 

 weeks ; but in truth Ins conclusions are founded on such absurdly 

 insufficient evidence that serious refutation is not needed. 



To return to the colony of rotifers. Since its establishment in 



1867 it has received no new immigrants, but as it increased and 



multiplied, some of its members, in a dry state, have been removed 



to stock new tanks for my friends. It is generally kept in a 



* ' The Beginnings of Life,' vol. ii., by Dr. Bastian. 



