THE VICTORIAN NATURALIST. 63 



wards to a dark mass lying about two-thirds of the total length 

 from the mouth ; on either side of this tubular process were two 

 kidney-shaped organs ; below, quite at the bottom, was a 

 spherical body made up of granules, each showing the spot and 

 inner spot known as nucleus and nucleolus ; down either side 

 were flat bands connecting internally the mouth organs with the 

 bottom of the bell. No organs of prehension were visible, and 

 the rotifer was in constant motion when unconfined, gliding 

 gracefully about with ever a constant stream flowing into the 

 mouth, carrying with it whatever particles or small animals were 

 floating in the neighbourhood. On placing a considerable 

 number in a trough at once, individuals could be seen in which 

 the dark spherical mass at the posterior end was replaced by a 

 young rotifer of about one-fifth of the dimensions of the parent ; in 

 others, the mass had something of the form of the adult. Here 

 was undoubtedly the young rotifer developing from the egg, and 

 the form was one which carried its young until fully developed. 

 A few specimens, in a decided minority, seemed to be of a 

 different species ; their shape was rudely triangular in one aspect, 

 this being due to a protuberance on one side of the posterior 

 extremity ; the interior was destitute of the complicated organs 

 possessed by the form I first attempted to describe, but instead 

 there was a spherical body connected by a process with the 

 protuberance mentioned, and a cord-like body extending down 

 the centre connected upwards with the centre of the fringe of 

 cilia. Furnished with these particulars, and a vivid mental 

 picture of the appearances presented, I applied myself to Hudson 

 and Gosse's " Rotifera," and had little difficulty in identifying the 

 rotifer as Asplanchna brightwellii. The second mentioned and 

 smaller form being there figured as the male of the British species. 

 This rotifer I found specially interesting on account of its being 

 the species in which the male rotifer was first discovered by Mr. 

 Brightwell in 1848. The male has no nutritive organs whatever, 

 being replaced by the apparently useless cord-like process passing 

 down the centre, the reproductive organs being the spherical 

 body and the process connecting it with the protuberance. The 

 horseshoe-shaped body in the female being the ovary, while the 

 dark mass encircled by it was described as the stomach, as I had 

 already inferred it to be by the contents, which in some cases 

 included infusorians of such a size as to strain the accommodation 

 to its extreme limit. I was struck with the exact agreement 

 between the figures of the British species in Hudson and Gosse's 

 work and the forms I had taken, and would be glad to hear the 

 opinion of some of our members as to whether Asplanchna 

 brightwtllii is indigenous, and if so, whether the distribution of 

 the species is world-wide ; or, on the other hand, if introduced, 

 how could a form be carried from Europe which apparently does 



