2o6 



HARD WICKK S SCIENCE- G OSSIP. 



The lorica is very flat, the average thickness of 

 fairly matured specimens being rather less than one- 

 fourth of the length of the dorsal plate. It is free 

 from flutings or tesselation and moderately firm. In 

 retraction the outline of the trunk is scarcely altered, 

 the proportion of loricated to membranous covering 

 being unusually great. In lateral view some irregular 

 wrinkles are visible in the integument lining the 

 lateral infold, which is well-marked (see dotted lines 

 Fig. i8o), although the plates are but little separated. 

 The dorsal plate, while in front as broad as the 

 ventral, is rather narrower behind, and is abruptly 

 and somewhat convexly truncate. The ventral plate 

 is excised anteriorly, permitting the head to be bent 

 down as shown in lateral view. The outline is 

 posteriorly completed by the dilated basal foot-joint, 

 which appears to be almost fixed and to have even 

 less freedom than usual in the genus. It is difficult 

 to trace lines indicating the junction of this joint 

 with the trunk on either dorsal or ventral side, but 

 those I have shown are, I think, correct. Indeed, 

 the joint is little more than a partly shelly, partly 

 membranous framework protecting and supporting 

 the sub-square lower foot -joint, which issues from the 

 under side and pivots on a blunt point arising from 

 the ventral plate. The toes, seen vertically, are 

 widest at the base, are then slightly pinched in, 

 again widen and finally taper to acute points without 

 either claws or shoulders. This curvature is confined 

 to the outer edges ; the inner being quite straight, 

 yet with a slight rugosity near the base. Seen 

 laterally the upper edges are decurved and the lower 

 nearly straight. 



The ample brain is in front bluntly pointed, but 

 %videns into three lobes, of which the central is the 

 greatest and bears near the inner side at its base the 

 bright rose-red eye. The wedge-shaped outline of 

 the prone face is interrupted by two knob-like pro- 

 jections whose nature and origin I have been unable 

 as yet to determine. The powerful mastax is well 

 forward, and I believe I have seen the jaws slightly 

 protruding into the buccal cavity. An oesophagus of 

 moderate length is attached to the inner side of 

 mastax and passing down it, proceeds to the stomach, 

 the lower part being in constant and rapid undulation. 

 The stomach, surmounted by the usual gastric glands, 

 is separated by a distinct constriction from a capacious 

 intestine, and in both ciliary action is apparent. The 

 vascular system embraces lateral canals, at least three 

 pairs of vibratile tags, and a small contractile vesicle 

 having a short period. Two band-like muscles pass 

 from the head down the back. Length ;— total, 

 ilo inch, toes about 5I5 inch, breadth 570 inch. 



In a gathering made in March 1890, from the 

 River Lea, below the Lea Bridge Waterworks, and 

 which I had placed on one side, I found some months 

 later a flourishing colony of Rotifera. The species 

 were few but very select, the most conspicuous being 

 Adineta oculata, only hitherto found, I believe, near 



Aberdeen. Along with it were many examples of 

 this Distyla, some Callidiita elegans, and some others. 

 The three forms named continued to flourish up to 

 the end of November, when the severe weather 

 wrought havoc among the colony. The Distylse 

 succumbed, but the other two species survived and 

 now after thirteen months the stock seems fairly 

 vigorous. It is noteworthy, that the supply of water 

 has never exceeded two ounces, any loss from 

 evaporation having been simply replaced from time 

 to time from the household supply, that no artificial 

 feeding was resorted to, and that no pond weeds were 

 present, the plant side of the balance of life being 

 represented principally by Scenedesmus and a 

 scanty growth of Oscillatoracese. 



Distyla mtisicola. 



Sp. Ch. — Lorica ovate, flattened, both anterior 

 edges truncate, almost straight, two very short lateral 

 points seen in utmost retraction. Dorsal plate rather 

 broader and longer than ventral, and rounded behind. 

 Ventral plate with a definite and shelly central portion 

 almost plane, from which a less stiff" integument 

 recedes laterally to the edge of the infold, and 

 posteriorly merges into that of the dilated basal joint 

 of the foot. Toes, tapering, acute, without claw or 

 shoulder. 



Numerous dead examples have occurred amongst 

 the sediment of water drained from Sphagnum, but I 

 have only as yet found one living specimen. The 

 remains seen have however shown the creature in 

 every position, and I find that as in D. depressa the 

 outline of the trunk is not greatly changed by retrac- 

 tion, and that extended the form is that of a long 

 oval, rather than that of an ellipse. The head is 

 wedge-shaped, the face rather prone, and the mastax 

 normal. Some very delicate markings can some- 

 times be seen on the shelly portion of the ventral 

 plate. The membranous lining of the infold is so 

 wrinkled as to give a peculiar scalloiDed appearance 

 to the lateral margins. The basal joint of the foot is 

 as in D. depressa, but even less distinct. The lower 

 joiut is much narrowed at the base. The blunt point 

 on which it pivots, appears however to arise from the 

 upper joint and not from the ventral plate. The 

 toes are thickest just above their middle and taper 

 thence to fine points. They appear straight in vertical 

 view, but seen laterally, they are sHghtly decurved, 

 with upwards-turning points. 



Length, extended, estimated at jj,^ inch ; retracted 

 sjg inch ; breadth, 3^ inch ; toes, -^-^-^ inch. 



Habitat, among roots of Sphagnum, Epping 

 Forest. 



Monostyla arcuata, 



Sp. Ch. — Lorica ovate, moderately depressed ; 

 occi^iital edge shallowly, pectoral edge deeply excised 

 in somewhat bow-shaped curve. Toe rather blade- 

 shaped tapering to an acute point, without claw or 

 shoiilder. 



