as Infusoria flagellata, 201 



pumila, Lamx., but is so excessively minute, and withal so 

 transparent, excepting tlie body proper, that under a magnify- 

 ing-power of live hundred diameters it appears to the casual 

 observer like a mere globular speck. It was discovered when 

 searching after specimens of Codonoeca costata with a power of 

 eight hundred diameters. Although sometimes met with in 

 groups of forty or fifty, it always appeared single. In its 

 general aspect it may be compared to an oval flask which is 

 supported by a slender stem (/'c?), and has a broad funnel in- 

 serted in its mouth. Upon close inspection we find that the 

 funnel [h) is a direct projection from the body (which hangs 

 freely within the flask, c c^), and is in no way connected with 

 the latter. 



The body proper has a dark fuscous colour, and consequently 

 is quite conspicuous. It is mainly oval in shape, but is con- 

 stricted anteriorly into a short thick neck (t), which terminates 

 in a truncate front. It hangs quite loosely within the calycle 

 (c) , and usually at a considerable distance from its parietes ; 

 but at the mouth (figs. 31, 32, c^) of the latter the neck (i) 

 presses so closely against it as to seem, without the most careful 

 scrutiny, to form a continuation with it. Occasionally, how- 

 ever, the neck narrows and retreats ■ from the aperture of the 

 calycle to such a degree as to allow a clear and unmistakeable 

 view (fig. 32) of the relations of the former to the latter. 



The collar (b), which has just now been likened to a funnel 

 set in the mouth of the flask-shaped calyx, is most frequently 

 seen in a very broadly expanded state (fig. 28, b), in outline 

 resembling a low, obtuse-angled, truncate cone inverted upon 

 the front of the body. It arises from the extreme circular 

 margin of the head {i) , and, widening to about twice the equa- 

 torial diameter of the calyx (c), terminates in a smooth edge 

 at an altitude which is hardly equal to one-quarter of the width 

 of its distal expanse. It is hyaline, and so extremely thin and 

 filmy as to require the most careful manipulation of the light, 

 even with so high a power as eight hundred diameters, in order 

 to define its boundaries clearly. In its plasticity it is even 

 more marvellous than that of Codosiga ; at least it exhibits it 

 over a far wider lateral range than the latter, and with equal 

 rapidity in its changes. In a few seconds it narrows from its 

 greatest expanse to the projDortions of an obverted acute-angled 

 cone (fig. 29, J), and at the same time assumes an altitude 

 which is equal to the length of the body ; and then, within an 

 equally short period, it contracts into the form of a cylinder 

 (fig. 30, b) whose height more than equals that of the calyx. 

 These changes are carried on with the same peculiar vibrations 

 as were noted in regard to Codosiga, reminding one of the 



