26 F. R. DIXOX-XUTTALL OX DIASCHIZA VENTRIPES. 



The width of the body gradually increases until two-thirds of 

 its length, whence it tapers to the roundly truncate posterior 

 extremity. 



The lorica is transparent, consisting of the four flexible plates 

 distinctive of the Diaschizae. The dorsal cleft is narrow, parallel- 

 sided, widening a very little posteriorly. The other edges of the 

 plates are curvilinear. 



The eye is cervical and double, having the appearance of two 

 eyes fused together, like that of D. exigua. It is placed on the 

 lower part of a large brain. 



The foot is short, quite ventral, and very much overhung by 

 the posterior projection of the body, by which this species can be 

 at once identified, and which has suggested the specific name. 

 The toes are short, sharp, and slightly decurved. The usual setae 

 on the foot common to all the Diaschizae are well marked. 



In front of the corona there is a decided crater-like projection, 

 which consists of the extended lips of the buccal orifice (the lower 

 lip curves down), giving it the apjDearance of a bird's beak, as 

 mentioned by Gosse in his description of D. ramphigera (" Supple- 

 ment," p. 98). This feature is more or less developed in all the 

 Diaschizae, and is not part of the trophi as suggested by him. All 

 round the buccal orifice there is a ring of long setae, which are 

 certainly tactile and most probably used to distinguish food from 

 other matter. 



The jaws are complex, apparently having two curved plates 

 attached to the unci and rami, forming a hollow, which can 

 be suddenly expanded, thus sucking in the food. This food 

 often consists of diatoms longer than the width of the animal 

 itself. 



The small dorsal antenna is well marked at the centre of the 

 circle of the head, above the large brain. 



The lateral antennae are very small and carried far back in the 

 lumbar region ; they end in a small bunch of long setae. 



This is a rather slow and graceful rotifer, quite a contrast to 

 the active and restless species like D. se'mia2)erta and paeta. It 

 obtains its food by grovelling in the flocculent matter on branches 

 of the waterweeds, and only swims apparently when it requires a 

 change of pasture. 



Total length, ttJ^ (127 /x) ; toes alone, ^^^ (23 /x) ; greatest 

 width, -^i^ (47 /z). Habitat : Knowsley Park, Lancashire. 



