HO LACINULARIA SOCIALIS 



can, I think, be little doubt that the former, like the latter, are subser- 

 vient to reproduction. 



There are then two kinds of reproductive bodies in Lacinularia : — 



1. Bodies which resemble true ova in their origin and subsequent 

 development, and which possess only a single vitellary membrane. 



2. Bodies, half as large again as the foregoing, which resemble the 

 ephippium of Daphnia ; like it have altogether three investments ; 

 and which do not resemble true ova either in their origin or subse- 

 quent development ; which, therefore, probably do not require fecun- 

 dation, and are thence to be considered as a mode of asexual 

 reproduction.! 



General Relations of the Rotifera. — It is one of the great blessings 

 and rewards of the study of nature that a minute and laborious 

 investigation of any one form tends to throw a light upon the structure 

 of whole classes of beings. It supplies us with a fulcrum whence the 

 whole zoological universe may be moved. I would illustrate this 

 truth by showing how, in my belief, the structure of Lacinularia, as 

 thus set forth, taken in conjunction with some other facts, gives us a 

 clue to the solution of the questio vexata of the zoological position of 

 the Rotifera, and thence to the serial affinities of a large portion of 

 the Invertebrata. 



The curious analogy in form between the genus Stephanoceros and 

 the Polyzoa has, I believe, been the chief consideration which has led 

 many naturalists, both in England and on the Continent, to arrange 

 the Polyzoa and Rotifera together. This has been done in two ways,, 

 either by denying the affinity of the Rotifera with the Vermes, and sO' 

 approximating them to the Polyzoa considered as organized on the 

 molluscous type, or, as Leuckhart has done, by admitting the affinity 

 of the Rotifera with the Vermes, but denying that of the Polyzoa with 

 the Mollusca. 



^ Leydig distingui-shes particularly between the ordinary, and what I have termed, the 

 ephippial ova. 



His description of the latter agrees essentially with that which has been given above ; but 

 he has not, I think, observed the genesis of the ephippial ova with sufficient care, and he 

 thence interprets their structure by supposing that they are ordinarily fecundated ova, which 

 have undergone a peculiar method of cleavage. The tendency of the observations detailed 

 above, on the other hand, is to show that they are not ova at all in the proper sense, but 

 peculiar buds like those of Aphis or Gyrodactyliis, and as such are capable of development 

 without fecundation. 



In the new edition of Pritchard's ' Infusoria,' it is stated (p. 620), that " in a recent paper 

 by Mr. Howard on this species, he states that there are two kinds of reproductive bodies — 

 one the ordinary ova, the other twice their size, representing gemmre.' No reference is 

 given to Mr. Howard's paper, and I have been at a loss to discover it, though desirous to do 

 justice to him if possible. 



