ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 819 



from the blood of Asellus aquaticus ; it is the first example of 

 a ciliated infusorian living in the blood of its host, and circulating 

 with the blood. The parasite does not, however, spend its entire 

 existence within the body of its host ; in the water containing Aselli 

 infected with the parasite, a number of infusoria were observed which 

 appeared to be identical with the individuals contained in the blood 

 of their host ; the liberation of these is certainly due on occasions to 

 the rupture of the terminal portion of the antennae, and possibly 

 always so ; these organs being long and delicate are more liable to 

 such fractures than any other part of the body ; it is interesting to 

 note that the parasites make use of an accidental lesion as a natural 

 way to leave the body of their host. The majority of the thus liberated 

 parasites die, but a good many survive ; these become encysted on a 

 filament of Conferva or similar locality ; even the body of an Asellus is 

 occasionally fixed upon. It is not, however, certain how the parasites 

 regain the body of their host. 



M. A. Schneider also describes* this infusorian, more especially 

 in regard to its method of reproduction. 



Conjugation takes place between the small ovoid individuals 

 which, instead of simply coupling, unite by temporary fusion of the 

 protoplasm. Before tliis fusion or at the moment that it takes place, 

 the nucleus and nucleolus, with which each is provided, undergo 

 modifications. The nucleus of the one elongates and extends for half 

 its length into the protoplasm of the other, which in its turn also 

 sends a portion of its nucleus to its neighbour. The two nuclei form, 

 at this moment, two parallel transverse bands, proceeding without 

 solution of continuity from the centre of one individual to that of the 

 other. The nucleoli are divided, and each individual has four. The 

 author is unable to say whether any exchange of these nucleoli takes 

 place. At the close of the conjugation each individual has six 

 globules, two large and four small : the former representing two 

 halves of the nucleus, of different origin ; the latter are the nucleoli. 

 The two large globules amalgamate and constitute the new nucleus, 

 and one of the small ones persists as nucleolus ; the other three are 

 reabsorbed. 



New Vorticella.f — Dr. A. C. Stokes describes a new species of 

 Vorticella found in the cedar swamps of New Jersey. V. limnetis 

 n. sp. is remarkable for the peculiar twisted appearance of the sheath 

 of the pedicle, a cliaractcristic wliich it has in common with V. octava 

 Stokes; but apart from its smooth, cuticular surface, it is easily dis- 

 tinguished from that species by the much smaller body, and the 

 greater abundance of the spirals and the conseq[uent shortness of their 

 curves. 



Difflugia cratera- X — Several species of animals belonging to 

 marine genera have lately been discovered in the deep waters of 

 certain fresh-water lakes in Switzerland. Among Infusoria, Tintin- 



* ComptoH Rf.nduH, c. (1885) pp. ].').52-3. 



t Tlie Mi(roHa)p(;, v. (188.0; pp. 14^-(j (1 flg.). 



X Zool. Arizci^., viii. (188r)) pp. 293-4. 



