of England and India. 21 



but the Amceba, and the next morning presented absolutely no- 

 thing but Coleps. The "rains" then set in, filled the tank, 

 and destroyed all trace of these Amoeba, since which period I 

 have never met with a similar occurrence. 



Amoeba monociliata, n. sp. PI. II. fig. 19. 



Polymorphic, charged with granules ; possessing a single large 

 cilium and villi on the posterior extremity. 



Hab. Fresh water. Locomotion reptant. 



Loc. Bombay. 



Obs. — I remember this specimen well. It stands figured in 

 my journal for May 1855 under two forms, as represented in 

 the plate, with no mention of the size, or anything more than 

 has been above stated. In the presence of the flagelliform organ 

 we seem to have perpetuated the one or two cilia with which the 

 young or monadine forms of the Rhizopoda, so far as my know- 

 ledge extends, are generally provided, but which disappear as 

 they grow older, leaving the more developed form inferior in 

 point of locomotive organs to the less matured one. Whether 

 the cilium of A. monociliata could be retracted or not I am not 

 enabled to decide, because I never observed more than one 

 specimen. But that we have an instance of this power in the 

 Ilhizopoda is seen, not only in the young of Acineta (which, 

 on issuing from the parent, commence with cilia which finally 

 become retracted and give place to capitate tentacula), but also 

 in the division of the free or stemless species, where one half 

 only puts forth cilia till its separation is thus completed, and 

 then retracts them again, to be followed by tentacula, as in the 

 young one — a fact which is well worth remembering, whether it 

 bears upon the question of A. monociliata being able to retract 

 its cilium or not, since it afibrds another instance of the extra- 

 ordinary extemporizing power of the Rhizopoda, viz. that of 

 being able to put forth vibratile ciha and retract them as the 

 occasion may require — organs which, in the other Infusoria, 

 when once developed, appear to be as unalterable in form as 

 their motions seem to depend on fixed muscular machinery. 



It is possible that this so-called species may be but a variety 

 oiPodostomafiligerum, Clap, et Lachm. (p. 441, pi. 31. figs. 4-6); 

 but, as above stated, I never saw but one specimen, and this did 

 not remain sufficiently long under observation to undergo more 

 changes in form than those which I have figured. 



DiFFLUGIA, Ehr. 

 Difflugia pijriformis, Perty (mihi). 

 A detailed description of this species will be found in the 

 'Annals' (ser. 3. vol. xii. p. 249), and I have nothing further to 



