INFUSORIAL ANIJTAICULES. 83 



the sides of the body, it is clear, in a very few days, all attempt at 

 an expression of their number must fail. 



The Rotatoria have generally been assumed to be hermaphrodite — 

 i. e., that each individual possesses a perfect male and female repro- 

 ductive apparatus, by which ova ai'e formed and fructified, without 

 the presence or contact of any other individual. Now, in these 

 animals, there has never been any difficulty as to the female repro- 

 ductive organs, which are very clear, well defined, and can be accu- 

 rately described, but, as to the male apparatus, the greatest diversity 

 of opinion has existed. 



Dujardin attempts no explanation, whilst Siebold candidly affirms, 

 that, with the absence of any precise knowledge as to the male 

 organs, it is stiU impossible to say whether the Rotatoria are herma- 

 phrodite, or have the sexes separate ; at the same time, he regards 

 the hypothesis of Ehrenberg on the subject, as untenable, and opposed 

 to probability. 



The clearing up of this questio vexata is, however, due to our 

 coimtryman. Mr. Brightwell, of Norwich, from whose discoveries 

 it is rendered highly probable, indeed, in part, certain, that the 

 sexes in Rotatoria are separate and distinct — existing in distinct 

 individuals. This careful observer met with a Eotatorial animal, 

 destitute of the internal organization of those heretofore described, but 

 having a very evident gland, communicating by an outlet with the 

 exterior of the body, the latter, moreover, was produced in some 

 measnre as a process perforated by the discharging tube. This 

 cuiious animal, of a smaller size than other Rotatoria, Mr. Brightwell 

 was at first disposed to consider another species, but subsequent 

 examinations, and the observation of occasional attachments with 

 the larger and undoubtedly female animals, convinced him, that he 

 had discovered a distinct male animal. Subsequent attention to the 

 subject has confirmed the fact of the dioecious nature of Rotatoria ; 

 and other observers, besides the discoverer, have witnessed the same 

 phenomenon. 



No objection can be raised ft-om the fact of the small size and im- 

 perfect organization of the newly discovered male animal, for similar 

 peculiarities are met with among other tribes of lower animals, such 

 as Annelida. 



G 2 



