Floscularia.'] infusotiiat. aximalcules. 621 



animalcules, together with the curved glandular band of nervous 

 matter in each leaflet of the vibratile organ, represent the system of 

 sensation ; the chewing movement of the mouth has been often 

 mistaken for the action of a heart. 



Melicerta ringens. — Case conical, granulated, resembling a 

 honey-comb of a brownish-red colour ; it is composed of small 

 lenticular bodies, expressly deposited by the animalcule from the 

 posterior alimentary opening, (and not foreign matter, like the 

 habitations of the larvae of the Phryganea;) these are aggluti- 

 nated by a peculiar viscid matter, also exuded, and afterwai'ds 

 hardened in the water. Into this tube the soft crystalline or 

 whitish animalcule can withdraw itself; when its flower-like 

 wheelwork is expanded, the vibratile cilia appear to run along 

 the margin of this organ, but, in fact, each single cilium only 

 turns itself upon its base, and the aggregate motion causes a 

 little whirlpool in the water, directed towards the mouth, situated 

 in the middle of the two large leaflets of this organ ; the eyes 

 are placed near the two other bent leaflets, which, according to 

 Dr. Ehrenberg, are analogous to a cleft upper lip of the dorsal 

 surface ; the discharging orifice is on the same side, and there- 

 fore the dorsal tail-like portion becomes a ventral member, or 

 foot. Fig. 386 exhibits an animalcule within its case, and having 

 the rotatory organ contracted : fig. 387 is another, with the latter 

 fully expanded ; in this drawing, an outline only of the case is given, 

 in order to show the internal structure. Two of the ova exhibit the 

 eyes and teeth, the latter are formed first. (P. 23, fig. 1.) Found 

 upon Lemnaand other aquatic plants. Length l-12th ; case l-24th ; 

 egg 1 -150th. 



" The case of M. ringens is formed of lenticular particles of 

 reddish-brown matter, thrown up by the animal from its discharging 

 orifice (which is at the upper part), and glued together by it in 

 lateral rows. This curious process may be detected on a careful 

 patient observation, and the animal may be made to build a coloured 

 case by mixing carmine or indigo with the water ; or a case com- 

 posed of alternate rows of blue and red, if the colours are carefully 

 changed." (Brightwell.) 



That the coloured pellets of the outer case are extended from the 



