1887.] ^^^ [Stokes. 



noted had withdrawn the tentacles, and had become encysted within the 

 lorica. The tentacles have tlierefore never been seen. These encysted 

 forms were undergoing one stage of reproduction. The entire endoplasm 

 is subdivided into very minute, remarkably active, biflagellate germs. 



Acineta bifaria, sp. nov. Figs. 23, 23, 24. 



Lorica, in side view, oval, the longest diameter less than twice the 

 height ; seen from above orbicular ; the entire surface minutely tubercu- 

 late ; pedicle very short, often only a small, inconspicuous, button-like 

 projection ; enclosed body attached to the posterior extremity only of the 

 lorica, and divided into two unequal parts, the posterior region often en- 

 tirelj' filling the cavity of tlie sheath, occasionally only about one-half 

 filling it, the anterior portion sul)spherical, habitually extruded beyond the 

 lorica aperture, and bearing the scattered capitate tentacles, the posterior 

 or loricate portion often coarsely and longitudinally striate ; endoplasm 

 granular ; contractile vesicles two, spherical, one situated near the lateral 

 border of the anterior body-half, the other on the opposite side of the 

 posterior or loricated region ; nucleus apparently broadly ovate or sub- 

 spherical, anteriorly placed ; reproduction by transverse fission of the 

 extruded anterior region, the embryo hypotrichous. Diameter of the 

 lorica, ^^^ inch. Eab. — An infusion of hay. 



The first noticeable sign of approaching reproductive fission consists in 

 an increased extrusion of the body substance, speedily followed by the 

 formation of fine cilia on the anterior surface, with the appearance of a 

 transverse constriction subceutrally situated on the extruded portion, as 

 in Fig. 23. This constriction deepens, the cilia increase in length, soon 

 entirely clothing the frontal region and one lateral margin, and, by the 

 time the division is completed, the posterior border as well. At the final 

 separation of the embryo it is ovate, coarsely granular, with a somewhat 

 conspicuous nucleus. It speedily becomes elongated and flattened, as in 

 Fig. 24, its length exceeding the height of the mature animalcule. The 

 cilia are confined to the extremities and the lower surface, while a few 

 short, capitate tentacles are scattered over the superior aspect. After the 

 departure of the embryo the remaining portion of the mature animalcule 

 withdraws itself into the lorica, as in Fig. 22, the anterior, subspherical 

 region remaining exposed and the tentacles protruded. The latter become 

 fevver in number, but are not entirely withdrawn during the reproductive 

 act. After it they become more numerous. 



The presence of the short, button-like pedicle of some individuals gives 

 the lorica an appearance closely resembling that of Solenophrya, to which 

 genus they might readily be relegated if not seen scattered among the 

 more abundant and more distinctly pedicellate forms. 



Acineta macrocauUs, sp. nov. Figs. 25, 26. 



Lorica obovate or subspherical. Lorica obovate, the length only slightly 

 exceeding the width, flexible, continuous, taking the form of the enclosed 



