3io 



THE SPOROZOA 



blochmanni ; and recently studied by Cohn, I.e., under the name Bertramia 

 asperospora (Fritsch). The trophozoites in this genus commence growth 

 as small rounded, uninucleate cells (Fig. 124, </, h), which become elongated, 

 sausage-shaped, or cylindrical bodies in B. asperospora (Fig. 124, a-c), or 

 flattened elliptical discs in B. capitellae, but in either case have a number 

 of nuclei, which multiply as growth proceeds (Fig. 124, i, j). In B. 



Fio. 124. 



Bertramia asperospora (Fritsch), from the body-cavity of Brachionus. a, young form with 

 opaque, evenly-granulated protoplasm and few refringent granules ; the nuclei, which are 

 difficult to make out clearly in the actual specimens, are small, and appear to be surrounded 

 each by a clear space, b and c, full-grown specimens, with large nuclei and clearer proto- 

 plasm, containing numerous refringent granules (r, gr). d and e, morula stages, derived from 

 ft and c by division of the body into segments centred round the nuclei, each cell so formed 

 being a spore. Between the spores a certain amount of intercellular substance or residual 

 protoplasm is left, in which the refringent granules seem to be imbedded. The morula may 

 break up forthwith and scatter the spores, or may first round itself off and form a spherical 

 cyst with a tough, fairly thick wall. /, empty, slightly shrunken cyst, from which the spores have 

 escaped g, free spore, or youngest unicellular trophozoite. h, i, j, commencing growth of the 

 trophozoite, with multiplication of the nuclei, which results ultimately in forms such as a and 

 6. Original figures, copied from drawings made with the camera lucida, x 1040. a-c, from 

 one preparation, and from the same Rotifer, d-j, from another. 



capitellae the number of nuclei present in the full-grown parasite is from 

 40 to 80, but in B. asperospora it is less, from 25 to 35, as a rule ; and 

 the latter species is also characterised by the possession of large refringent 

 granules in its protoplasm, which is limited by a distinct but delicate 

 cuticle. When growth is completed, the body becomes segmented to form 

 a mulberry-like mass of spores, each centred round one of the nuclei 

 (Fig. 124, d, e). 



In B. asperospora the body-form of the morula is not different at first 



