100 THE ROTIFERA. 
is ovate, not so pyriform as in cornuta. The edges of the upper and lower plates come 
closer together; for the anterior two-thirds the edge of the dorsal plate is about level 
with that of the ventral, but much exceeds it inlength. The dorsal is straightly truncate 
behind, with the margin on each side, following the ovate outline and descending much 
farther, so as to form two points. The dorsal surface is somewhat coarsely tesselated, 
like that of Cathypna rusticula, but with the pattern slightly different (Pl. XXIV., 
fig. 6). The whole surface appears as if irregularly crumpled, interfering with distinct 
definition in spite of the transparency. The head is a low truncate cone, produced into 
a number of slight frontal eminences, on which the locomotive cilia are arranged in tufts 
or bundles. These do not appear to create sensible vortices in the surrounding water. 
This species is, I conjecture, the fig. 22 of Mr. J. E. Lord (‘‘ Microsc. News,” June 
1884, page 146), as M. cornuta is his fig. 21. I therefore distinguish it with his name. 
I have met with it myself, on rare occasions recently, among decaying vegetation in the 
water of Woolston Pond, and abundantly in water kindly sent me by Miss Saunders. 
Length, 5}, to ;}4y inch. Habitat. Woolston; Newbury ; Dundee (P.H.G.): rare. 
There is a form,—of which Iam almost inclined to make a separate species,—in general 
like Lordi, but remarkable for the excessive length and slenderness of the toe, which 
almost equals the length of the lorica. It may be but an extreme var. of the present 
form. Yet the lorica seems to lack the square excavation behind, and to be more pyri- 
form in outline, running off in front into broader lobes, as in lunaris. This I have found 
in water sent me by Mr. Bolton from Sutton Park.—P.H.G.] 
M. quapripentata, Ehrenberg. 
(Pl. XXV. fig. 8.) 
Monostyla quadridentata : fs 4 Ehrenberg, Die Infus. 1838, p. 459, Taf. lvii., fig. 5. 
(SP. CH. Lorica nearly circular, greatly depressed, especially behind ; front deeply 
cleft, with two horn-like spines decurved and expanding at their tips. 
The horns well distinguish this form. During retraction these are drawn together, 
and made even to cross each other (fig. c). Besides these, and outside them, the 
dorsal plate projects into a broad-based triangular point on each side; while the pectoral 
margin forms a flexible membrane, very deeply cleft in the middle, and further deepened 
at will. The hind part is exceedingly flattened, merging into the foot, of which the last 
joint is cubical, with a central notch. Here is articulated the toe, rod-shaped, but that 
the outline of each side, instead of being straight, is strongly waved: an appearance 
which may possibly indicate the waves of a tenacious mucus. At one-fifth from the tip 
a double shoulder, rounded rather than rectangular, leaves the usual acute claw. The 
head protrudes (fig. b), much as described in cornuta. Of the trophi, the mallei (fig. d) are 
remarkable for a conspicuous horn projecting upward from each angle. The gastric glands 
are large; there is a large separate intestine, and also an ample contractile vesicle. 
Several examples have occurred to my observation. In one I was witness to a curious 
phenomenon. A large shelled Infusory, Arcella vulgaris, was within the Monostyla, 
though how it had managed to force its way in, I cannot imagine, for it almost filled the 
cavity of the lorica. Its fleshy processes were protruding in front, and, by the death of 
the Arcella, unable, I suppose, after it had devoured its host, to get out, these processes 
gradually lengthened inordinately. It was a curious sight.—P.H.G.] 
Length, 3, to z's; inch; of lorica, y1, to 745 inch. Habitat. Barking ; Stratford ; 
Maidenhead ; Hampstead (P.H.G.); among duckweed, in pools and ditches: rare. 

