120 Transactions. — Zoology. 



part of the body. The head is not distinctly marked off from 

 the rest of the body ; it is bent downwards, so that the corona 

 is inclined at an angle of 45° to the plane of the rest of the 

 body. The lorica is very poorly developed, and seems to be 

 more or less pliable. It becomes very soft indeed in the 

 posterior region of the body, but is a little stronger in front, 

 where it forms a small spine on each side. This spine has a 

 much smaller spine just below it. The trophi are of the 

 abnormal forcipate type, and show the want of symmetry 

 characteristic of the family. The left malleus is very long, 

 but the right one is greatly reduced, both in thickness and 

 length. The stomach is surrounded by a number of brown 

 highly refractive bodies, which seem like glands. No brain 

 was observed. The eye is small and round ; it is situated 

 above the anterior part of the mastax, and is well back within 

 the body, being very far behind the anterior border of the 

 lorica, which may be said to mark the head from the body. 

 The ovary is small, and is situated posterior to and below the 

 stomach. 



This Rotifer's movements are active and restless. It 

 almost always swims on its side — at least, when on a glass 

 slide. Its jaws worked only very rarely. Occasionally it 

 anchored by the tip of its style, held this rigid, and waved 

 itself about from the joint at its foot. 



Hab. ThepooL 



Very common in autumn. 



VII. Mastigocerca rectocaudaUis, sp. nov. Plate IX., figs, vii., 

 vii.a. 



Specific characters : Body a long oval, no ridge on lorica. 

 Toe exactly straight, and slightly longer than the body and 

 head. Substyles 4, minute. 



No colour except the small red eye. Seen from the side 

 this is a shghtly hump-backed Rotifer, with the highest point 

 in the middle ; it is also broadest in the middle, and tapers 

 towards the extremities, more so towards the posterior one 

 of course. A symmetrical and rather graceful Eotifer. 

 The foot is short and rather indistinct, but it has an 

 immensely long style, quite as long as the rest of the body. 

 This, as in M. fiectocaudahcs, is always carried at an angle 

 to the general direction of the body. It is surrounded by 

 three or four minute substyles. The head projects forwards 

 and downwards from the body. The cilia must be very small, 

 for I never saw them. The lorica is soft and flexible, 

 though more developed than in M. flcctocaudatus. There is 

 a small median dorsal cleft, and the hinder border over the 

 foot is concave. The mastax is of the asymmetrical type. 

 The length and strength of the right malleus are very much 



