98 THE KOTIFERA. 



suggest that Cathypna is Monosti/la with the toe cleft tlirougL the middle, or that 

 Monostyla is Cathypna with its two parallel toes soldered mto oue. — P.H.G.] 



M. LUNAEis, Ehrenberg. 



(PI. XXV. fig. 2.) 



Monostyla lunaris .... Ehrenberg, Die Infus. 1838, p. 460, Taf. !vii., fig. fi. 



[SP. CH. Lorica broadly ovate, the dorsal plate round and greatly elevated, the 

 ventral nearly flat ; both in front projected into wide, triangular, flattened points, be- 

 tween which the edge is deeply excavate ; toe straight, rod-shaped ; claw protruded 

 between two slender spines. 



The gibbous lorica descends abruptly before it is produced into the wide clear 

 triangular lobes in front. And there seems no noticeable difference in outline, either of 

 the lobes or of the intervening sinus, between the dorsal and the ventral plates. For, 

 in retraction, these are very firmly appressed, with a common outUne ; so that no 

 change of position, and no focusing, makes the eye cognizant of more than a single, 

 somewhat thickened, crescentic line. The general figure is so elevated that it is more 

 than half a sphere, if we neglect the inangulatiou of the lateral sulcus, which, in this 

 species, is not deep. The foot-bulb appears to lie in a hollow of the ventral plate ; it is 

 wide and kidney-shaped behind, where the straight-edged, rod-hke toe is articulated. 

 This terminates in a slender acute claw, not with a rectangular shoulder ; but with 

 a pair of fine points, between which the claw is, as it were, imbedded. Herr Eck- 

 stein describes certain appearances, which he interprets of the thickened lorica- 

 structure, for strengthening the foot against the violent strains endured as the animal 

 throws itself to and fro. He also depicts certain pale-red specks and excessively fine 

 lines, going upwards fi'om the claw, which he would connect with the nervous system, 

 as well as with the mucous glands. "The rotatory organ is simple, but almost retired, 

 so that only a shght elevation with a single seta projects out of the lorica. When it is 

 extended, we discern two great lobes, which overlap the lorica-edge on each side, over- 

 reaching each other dorsally, but ventrally running off into the buccal orifice " (Ibid.). 



A specimen in my possession, anchored by the toe to the glass of the live-box, threw 

 itself \-igorouslj- into all possible positions, for twenty-four hours, without once removing ; ' 

 all that time, so far as observed, active in this special way, but close shut-up. The 

 movements, indeed, though constant, were not incessant, but very forceful, spasmodic, 

 and sudden. In general the animal is clear and colourless : of this specimen, the whole 

 body was stained of a yellow-brown hue, like sherry wine, so deep, while yet clear, that 

 no definition of \'iscera was possible. Yet the red eye was now and then defined, and, 

 under direct sunlight, came out very rich, and of a deep crimson hue. The great tri- 

 angular lobes of the lorica, being very thin, were quite colourless and glass-like. — P.H.G.] 



length. When extended, -yj^r to -|:nT hich. Habitat. Woolston ; Sandhurst; 

 Thames, near Heading ; Snaresbrook (P.H.G.) : mostly in pools : not unconmion. 



M. COENUTA, Ehrenberg. 



(PI. XXV. fig. 1.) 



Monostyla eornida .... Ehrenberg, Die Infus. 18S8, y. 459, Taf. Ivii. fig. 4. 



[SP. CH. Lorica ovate, moderately depressed, the front shallowly incurved; toe 

 somewhat blade-shajjed, the claw without a distinct shoulder. 



This species is very much like M. lunaris, so as, when retracted, scarcely to be dis- 

 tinguished from it except that the anterior dorsal edge of the lorica is slightly less 

 incurved. It is smaller, and rather more oval in outline ; in the act of extruding the 



' During the latter part of the time, however, it became very sluggish, and less willing to move and 

 jerk about. 



