258 Prof. H. James-Clark on the Spongie ciliate: 
gella recall Anisonema (§ 13) most vividly to mind; but, on 
the other hand, the group of cilia (c/) in the obliquely longi- 
tudinal furrow (f) in close proximity to, and evidently acti 
more or less as allies with, the flagella (1, #), find their pa- 
rallel in the ‘‘ proboscis-like lash” (fig. 75, 7) and vestibular 
cilia (c/) in the oblique buccal furrow of Plewronema (§ 16) 
and Dysteria (§ 15). How closely allied the two latter are to 
the former is not the immediate question here; it is, are they 
related at all? We think there can be no hesitation in reply- 
ing in the affirmative; but in order that the reader may have 
the proof before his eyes, I think it will not be out of place, in 
this memoir, to introduce some of the undoubted Ciliata which 
possess at the same time organs that are as truly flagellate in 
character as are the flagella of Anisonema, Astasia, &c. The 
genus Dysteria shall be our first example. 
§ 15. DysrreriA, Huxley. 
Dysteria prorefrons, Jas.-Clk.* Pl. VII. figs. 77, 78. 
This species “is an infusorian between two leaves. or flexible 
shells (v, v!) of unequal width, which are united by a sort of 
hinge along the left border, and gaping to a more than equal 
extent along the right side, where the upper one (v) far over- 
hangs the other (v', 64) throughout the whole length of its free 
edge. ‘The broader or dorsal shell (v) is convex towards the 
eye, and the whole organization lies within its concavity, 
whilst the narrower one (dk, v!) is flat, simply covering the 
body, and as a natural consequence does not include any 
of it. The open space between them is endowed with a row 
of closely set, large vibratile cilia (c/), which differ in size ac- 
cording to their position, those in front being by far the longest, 
and those along the side scarcely more than half as long ; and, 
in addition, there is one (ff) which, from its great size, has 
more of the character of a proboscis or prehensory flagellum, 
and is attached nearly at the extreme anterior border of the 
row (cl). 
** It is not an easy matter in this case to determine how much 
of the one-sided, cilia-bordered furrow corresponds to the disk 
or vestibule of Hpistylis, Stentor, Paramecium, or Pleuronema; 
nor does it affect the question of the degree of obliquity of the 
conformation of this animal, so long as we see that, whatever 
it may be, either wholly or in part a vestibule, it is at least 
extremely oblique, and that it is not possible to view it from 
any point but that the body appears asymmetrical in relation 
to it. 
* See ‘Mind in Nature,’ wt supr. p. 171, fig. 100. 
