214 M. C. Meresclikowsky on some 



being covered with cilia. It seems very strange that such an 

 eminent student of the Infusoria as M. Stein did not direct 

 attention to this form, and that in general he has not mentioned 

 the work of Clapar^de and Lachmann in treating of the family 

 Ervilina. I propose, therefore, to call the Infusorian in ques- 

 tion Trochilia oliva. As for the Trochilia 'polonica^ Wrzesn., 

 found by M. Wrzesniowski in the fresh waters of Poland, that 

 species has very little to distinguish it from T. jpalustris^ 

 Stein, 



With regard to the fifth species, which I have just de- 

 scribed under the name of Trochilia marina^ it is very distinct 

 from all the other known species. It most nearly approaches 

 Trochilia oliva, from which it is distinguished by the general 

 form of the body, the two dorsal grooves, and the absence of 

 the black pigment spot at the anterior part, which is so 

 characteristic of T. oliva. 



At present, therefore, we shall have five species of the 

 genus Trochilia, three marine and two freshwater. Of the 

 first three species, one {T. oliva) inhabits the northern seas, 

 and the other two [T. sigmoides and T. marina) the seas of 

 the south of Europe. Length of the animal 0*033 millim. 



Acineta livadiana, sp. n. 

 (PL XII. fig. 10.) 



Diagn. Concha ovalis, superiore parte, qua intus flectitur 

 atque cum corpore conjungitur, truncata ; pediculus tenuis, 

 cylindricus, paulo quam corpus longior, scapo centrali, 



Loc. Black Sea, Livadia, surface. 



Descr. The carapace of the animal is regularly oval, except 

 at the superior exteremity, where it is suddenly truncated, 

 and furnished with a wide orifice, through which the suckers 

 are seen to pass. The margins of the orifice bend in towards 

 the interior of the carapace, and are produced there to some 

 distance, forming a short interior tube. It is at the margin of 

 this interior tube, and only at this margin, that the body of 

 the animal is attached ; in all other parts it remains freely 

 suspended in the cavity of the carapace, occupying more than 

 half its space. The body is almost regularly round, with its 

 contours undulated and changing continually, these contours 

 thus demonstrating the constant amoeboid movement of the 

 living animal. The protoplasm is strongly granular, which 

 renders it rather opaque and at the same time makes it im- 

 possible to see the nucleus ; but, on the other hand, a con- 

 tractile vesicle situated in the ectosarcode is easily distin- 

 guished. The suckers, terminated by a knob, are not longer 

 than the diameter of the body ; they are about twenty-five in 



