102 



points. The retraction of the parts is too rapid to allow these to be 

 accurately copied. 



Fig. D represents the left side of the animal. The abdominal 

 viscera preclude any distinct sight of the muscles on the ventral 

 region, but on the dorsal parts they are seen numerously. Many of 

 those already described are recognisable, and are marked with the 

 same numbers. There are some, however, additional ; chiefly situate 

 near the mesial line of the dorsum, perhaps not in pairs. One (23) 

 proceeds from the back of the head to a point between the second 

 and third transverse bands ; where another (24) commences and 

 reaches to the last transverse band. Of both, the insertions are in 

 the skin, and the use is evidently longitudinal contraction. A band 

 or cord (25) seems to proceed from the occipital sac to the middle of 

 the back, between the third and fourth transverse band, and helps to 

 draw it downward and backward. Above this are two cord-like 

 organs, which, I think, are not muscles, but vessels, or perhaps ner- 

 vous cords, issuing from the centre of the back of the ganglion, and 

 jutting out into two arches, one above the other: the lower (26) I 

 have not traced far, but the upper (27) runs down in a loose, 

 tortuous manner for some short distance along the back, when I 

 cease to discern it. It is this serpentine slackness which makes me 

 doubt its muscular character. 28 is the great frontal tube of the 

 ganglion, showing its forward curvature. 



Such then are some of the details of the structure of this tiny 

 animal ; many of them I have observed also in other species 

 and genera, which are possessed of organs of which this species 

 is deprived. They prove that the minuteness of the animals of this 

 class does not preclude them from having an organization most ela- 

 borate and complex; and, I think, justify the belief that the Rotifera 

 occupy a place in the scale of animal life much higher than that 

 which has been commonly assigned to them. 



Of the manners of the species I have not much to say. In a phial 

 it frequently clings to the sides of the glass, and appears sluggish ; 

 but when put into a live-box, it is active, especially if there be any 

 Conferva, or leaves of Chara, or roots of Lemna in the water. 

 Among these it crawls about nimbly and impatiently, like a cater- 

 pillar, pushing itself in every direction, by means of its two-toed 

 foot, and by the elongation and contraction of its body ; but without 

 any definite course. The extent to which the fore parts are intro- 

 verted is remarkable, the gizzard, as already observed, being some- 

 times made to touch the liinder part of the body. This action 



