from the Cell-contents of the Characese. 117 



first, into considering this as an alternating form of Euglena. I 

 have since almost satisfied myself that Euglena conjugates, and 

 that the cells which I have termed embryonic pass into Euglenm. 

 But had these cells not been present, there would still have been 

 room for doubt, inasmuch as a development of the same kind 

 takes place in some AmoRbce^ apparently in connexion with the 

 nucleus alone, with which Euglena also is provided (fig. 11) ; at 

 the same time that we know the Amcebce to produce embryonic 

 cells like Spongilla, which cells again are like those of Euglena. 

 Some Amoeba at least then, propagating by germs or gemmae, 

 according as the granules are set free singly or in masses, as 

 well as by embryonic cells, it might be questioned whether 

 Euglena does not also possess these two processes. Again, when 

 we know from Stein, as before mentioned, that Vorticellce pass 

 into Acinetce, and Acinetce produce full-formed Vorticellce — and 

 I have seen some Amoeba also produce full-formed Vorticella — 

 it becomes necessary to ascertain among these changes, what are 

 parasitic or foreign developments, and what are merely alternating 

 forms of the same species, — inquiries which are extremely 

 intricate and perplexing, but which must be prosecuted tho- 

 roughly before we shall be able to adjust these matters, or 

 arrive at a true history of the vital oeconomy of both Infusoria 

 and Algse. 



With reference to the development of the "ciliated sacs'' 

 mentioned at p. 14, I have since ascertained, that the variety of 

 forms which they assumed depended upon their having been 

 forced from their cysts before they were fully developed ; for I 

 have since not only had an opportunity of examining them when 

 just liberated from the latter in the natural way, but of watching 

 for a long time two individuals of large size and full develop- 

 ment, which I found free among some filaments of Cladophora, 

 Having thus called attention to this development, I will describe 

 the infusorium which appears to be the source of it. It is a 

 Paramecium closely allied to Nassula, and, from the likeness of 

 the oral orifice to the human ear, I propose for it the name of 

 " OtostomaJ' 



Otostoma, H. J. C. (new species) (PL IX. figs. 6, 7, 8). 

 Body ovoid, of a light brown colour, covered with longitudinal 

 lines of cilia (figs. 7, 8). Mouth ear-shaped, in a depression situ- 

 ated about the junction of the anterior with the middle third of the 

 infusorium (fig. 7 a) ; buccal cavity broad, short, curved down- 

 wards, and a little upon itself outwards, plicated longitudinally 

 in parallel lines (fig. 6 a). Anus terminal; gland or nucleus 

 long, fusiform (fig. 7 c), situated between the buccal cavity and 

 the contracting vesicles (fig. 7 d, d)^ which are double, an^ 



