On (Ecistes umheUa and other Rotifers. By C. T. Hudson. 3 



spite of the severe weather, which seems to have killed all their 

 brethren in the ponds. 



(E. umheUa has two well-marked red eyes which can be seen on 

 looking down through the disk ; they are situated well within the 

 animal, below the disk, and towards the dorsal side, that is, towards 

 the side where the mouth is not. 



Ehrenberg's family, CEcistina, ought of course to be included in 

 the family of the Melicertans, but I agree with Mr. Wills that the 

 genus CEcistes ought to be retained, as we have now no less than 

 five species ; viz. (E. crystaUinus ; Mr. Davis' new pair, CE. inter- 

 medius and Gi. hngicornis ; Mr. Tatem's CE. jjilula ; and Mr. 

 Oxley's (E. umheUa. 



Conochihis volvox. — I had the pleasure of reading Mr. Davis' 

 excellent paper on this most curious rotifer,* just after I had 

 been drawing it from a few specimens which had survived the 

 transit from London to CHfton. The creature is a bad traveller, 

 not a single sphere remained unbroken ; and indeed the tube con- 

 tained no group with more than four rotifers in the cluster. In 

 some respects this was an advantage, as it enabled me to see much 

 more clearly than I otherwise should have done the animal's 

 structure. First let me say that Mr. Davis' account of this rotifer 

 is most accurate. He is quite right in pointing out that there 

 are the usual pair of setae-bearing antennee, one on either side of 

 the mouth, not four conical papillae, each with a bristle, as Ehren- 

 berg asserts. He correctly states that the line of cilia is inter- 

 rupted in one part of the disk, and that the notch in tie cilia is not 

 where the mouth is. Mr. l)avis has also most clearly shown the 

 peculiarity of this rotifer's structure in having its mouth and anal 

 aperture on the same side : and in its fringe of large cilia enclosing 

 that of the small cilia as well as the mouth ; instead of its being 

 enclosed by the smaller cilia, and of the mouth's lying between the 

 two fringes. Mr. F. A. Bedwell has given an admirable and most 

 forcible illustration of the difference between the trochal disk of 

 Conochihis and that of Melicerta in his capital paper on the build- 

 ing apparatus of Melicerta ring/ens. 



The arrangement of the parts is so curious in Conochihis, and 

 so exasperating to a classifier, that I may venture to suggest even 

 a third way of considering them. If a crochet hook were supposed 

 to be pushed through the centre of the disk, down the middle line 

 of the body, and hooked on to the end of the foot, then on draw- 

 ing the hook right back again, the animal would be turned inside out 

 like the inverted finger of a glove, and be pulled through its own 

 disk ; and the relative position of its organs would be nearly that of 

 an ordinary Melicertan. In the drawing that I have given of a 

 Conochilus, it will be seen that the anal aperture lies remarkably 



* ' M. M. J.,' vol. xvi. p. 1. 



B 2 



