138 Prof. H. James-Clark on the Spongie ciliate 
contracts so vigorously and abruptly, at the rate of stax times a 
minute, that there seems to be a quite sensible shock over that 
side of the body in which it is imbedded. | 
The reproductive organ may possibly be represented by the 
very conspicuous, bright, highly refracting, colourless, oil-like 
globule (x), which is enclosed in a clear vesicle, and appears 
to be so constantly present in the depths of the posterior third 
of the body. Its position seems to be invariably on that side 
of the transverse axial plane which is opposite to that in which 
the contractile vesicle (cv) lies. Nothing further of a positive 
nature can be said in regard to this body; but we may con- 
jecture that, inasmuch as it cannot well be assigned to any 
other office, not even to that of an eye-spot, it is im all proba- 
bility an organ of reproduction. 
In regard to the stem (fig. 38, pd), it may be added that, 
although it appears to be of the simplest nature—a mere 
gossamer thread as it were, it is none the less positive, as a 
support, than that of Anthophysa (figs. 47, 48, 49, pd), and 
must indeed possess a similar self-reliant power in order to 
keep the body in the same relative position in regard to the 
object to which it is attached, or to sustain it in an upright 
attitude at a time when the flagellum is quiet and there is. 
consequently no other means of preventing the animal from 
sinking down upon the nearest fixed point. 
§ 2. Monas neglecta, nov. sp. Pl. V. figs. 5, 54, 5», 6. 
To a casual observer this species would appear to be one of . 
the varieties of Monas termo of §1; and I must confess that, 
under an amplification of only five hundred diameters, the 
mistake would be easily made, unless one had become perfectly 
familiar with the two by prolonged study with a much higher 
magnifying-power. ‘There is, though, a physiological differ- 
ence which can be observed when all others could scarcely be 
noted, which is this: the rate of the systole of the contractile 
vesicle (cv) of this species is double that of Monas termo. Like 
the latter it enjoys two diverse conditions of life—namely, a 
fixed (figs. 5, 5%, 6) and a free (fig. 5°) state,—frequents the same 
habitat, progresses with the same means and mode of loco- 
motion, and obtains its food by similar prehensile organs, and 
swallows it in the same manner. 
The form of the body is that of an oval, but terminates an- 
teriorly in an obliquely truncate front; or, rather, one side of 
the front projects in the form of a low, rounded prominence, 
which constitutes the lip (jp). The posterior end is either 
broadly rounded or very bluntly pointed where the pedicel (pd) 
is attached. The colour is either greyish or there is none at all. 
