256 Prof. H. James-Clark on the Spongie ciliate 
truly contractile, but rather flexible, and exhibits its muscular 
power by bending itself into coils or zigzags. Occasionally 
specimens are met with which have an additional pair of fla- 
gella (fig, 69, 7%), of a more delicate kind, attached near the 
others. ‘That these originate as a preliminary step to fissi- 
gemmation, although that phenomenon was not witnessed in 
this case, there can be scarcely a doubt, inasmuch as it accords 
perfectly with what has been observed in Anthophysa (p. 213). 
The mouth has not been demonstrated to a certainty, by 
actually seeing food pass into it; but an approximative tad 
mination was reached by observing particles of matter, which 
were brought down by the prehensile flagellum (fl), pass into 
the body somewhere near the front, and apparently within the 
compass of the covered way, 
The anus (figs. 65, 66, a) was adjudged to be at the posterior 
end of the animal, by noticing, in a couple of instances only, 
a clear, more or less irregular, rounded mass in this region, 
and its final disappearance while under observation; but the 
substance was so transparent that it was not possible to decide 
positively whether it made its exit upon the dorsal or the 
ventral side, 
_ The contractile vesicle (cv) is a comparatively large organ, 
with a rounded contour when in full diastole, and quite faint 
and inconspicuous. It lies above the base of the gubernaclum 
(fl?), the expanded base of the latter appearing at times to 
form a part of it, and by its movements (causing an alternation 
in light and shade) tends to mislead one into the belief that 
systole is very irregular, A careful adjustment of the lens, 
however, reveals the true pulsation, iad shows that the sys- 
tole has a very slow rate, 
§ 14. Hereromastix, Jas.-Clk.* 
Heteromastix protetformis, Jas.-Clk. Pl. VII. figs. 70-74. 
I shall not describe this infusorian in the same systematic 
manner that has been adopted in treating of previous genera, 
because I do not know much about its internal organization ; 
but in order that the direct alliance of the Flagellata with the 
Ciliata may be illustrated in this memoir in its strongest light, 
and inasmuch as Heteromastix is by far the best example of 
such a transition between the two above-mentioned orders, 
T shall take the liberty of quoting what I have already pub- 
lished in regard to it in another place. | 
“Here is an infusorian (figs. 70-74), from fresh water, 
* érepos, dissimilar; pdori€,alash. This genus was originally de- 
scribed in my published volume of Lowell Lectures, ‘Mind in Nature,’ 
p- 146, fig. 88, . + See note *, 
