136 ON SOME NEW 



suggests that the upper portion may be repaired, or even the newly- 

 formed lorica of a young individual built up on the fragmentary 

 basal portion of a deserted test. I have seen many specimens of 

 this Flatycoia, and they all have the same peculiarity. The length 

 of the lorica is i-3ooth inch. The surface of a lorica, seen from 

 above, and presumed to be this species, presented a number of 

 fine transverse striae. 



The animal is very large ; and if all the specimens I have seen 

 are of the same species, it can protrude itself to an extraordinary 

 extent, the height considerably exceeding the length of the lorica. 

 This, however, was in a single small specimen (Fig. 7), which pre- 

 sented the further peculiarity that the colourless neck was quite 

 two-thirds of the length of the lorica. It is possible this may be 

 another species. As a rule, Bicolor is not protruded nearly so far ; 

 the total height being about two-thirds the length. At times the 

 body is suddenly and very much constricted just at the margin of 

 the collar, so as to present somewhat the form of an hour-glass 



(Fig. 4). 



The peristome is unusually thick and prominent, and the ciliary 

 disc is much elevated. By far the most interesting point, however, 

 about the animal is the presence of a very delicate membranous 

 hood, which has a large oval opening, is retractile, and projects 

 backwards from the top of the ciliary disc, covering the oval open- 

 ing. I do not know of any similar structure amongst the Infusoria. 

 De Fromentel, in describing another species of this genus, P. 

 gracilis^ mentions that the vestibular bristle, in addition to being 

 conspicuous, is often reflexed in a ring-Uke form, and so figures it. 

 I quote this from Mr. Kent's Manual, where the figure is not re- 

 produced. It is probable that Gracilis has a hood like Bicolor. 

 Mr. Kent remarks that from De Fromentel's description and illus- 

 tration it would appear that Gracilis has a distinct membranous lip 

 or collar, such as occurs in the genera Opercularia and Lagenophrys. 

 These collars, however, bear no sort of resemblance to the hood 

 of Bicolor. I am not quite clear as to the function of this hood. 

 I think I once saw the digested food issuing from this hood, and it 

 is possible its use may be to keep the digested food away from the 

 action of the cilia, and so prevent it from being again brought in 

 by the current. 



