iNFTTsoniAt, antmat,otjt,t;s. C>1 



recent extended and careful inquiries of "Wagner, Leuckhart, and 

 Kolliker, (Cyclopaedia Anatomy Art. " Semen"), have satisfactorily 

 proved to those wi'iters the non-aiiimalcular character of those 

 organic particles. They have explained their peculiar development, 

 and the essential part they play in the propagation of animals, aa 

 low in the scale as the Rotatoria. 



The discovery of the peculiar spiral and moveable fibres in the 

 antheridia of mosses, by Unger, and called spermatozoa, having 

 kindled much interest, induced me to introduce a description and 

 drawing of them in the first edition (which is retained in the present) 

 under the genus Spirillum. The experiments and observations of 

 Fritsche and others, have exploded the idea (in the opinion of 

 naturalists generally) of those bodies being spermatozoa, or of their 

 possessing an animal nature. 



In accordance with Ehrenberg's views of the digestive system, he 

 divides the Polygastrica into P. anentera and P. enterodela ; the 

 former destitute of an intestine comiecting the several stomach sacs, 

 each of which opens dii'cctly into the mouth ; the latter possessing 

 one, which, from the various ways it is arranged, gives rise to a 

 further division into cycloccBla, orthocwla, and campylocoela. In the 

 first of these, the intestine is so ciu:ved upon itself, that its two 

 extremities unite at the oral opening — ex. in Yorticellina, and in 

 Ophiydina ; in the second, it passes straight through the axis of the 

 body — ex. in Enchelia and Colepina ; in the third, it is more or less 

 contorted— ex. in Leucophiys, Trachelina, &c. 



But the consideration of the relative position of the oral and anal 

 openings, led Ehrenberg to devise yet another arrangement of the 

 Polygastrica, calling those forms anopisthia, where, as in Cycloccda, 

 the two apertures are united at the fore extremity ; enantiotreta, in 

 which, whether in orthocoela or campylocoela, the apertui-es are at 

 opposite ends of the animal ; allotreta, where one is terminal, the 

 other lateral ; and, lastly, catotrcta, where the two orifices are 

 lateral. 



As for the anentera, he divided them into three sections ; the first, 

 comprising those without feet or appendages, Gymnica ; the second, 

 with variable appendages or processes, Pseudopoda; and the thii'd, 

 with cilia, Epitricha. (see Tables, Part III.) 



