98 Miscellaneous. 



the body immediately to resume its normal contour when this has 

 been modified by any obstacle. The endosarc consists of clear and 

 liquid sarcode, at the periphery of which there exists a layer of large 

 opaque granules. 



The nucleus is free in the general cavity, and, following the move- 

 ments of the body, can move from one extremity to the other. Its 

 form is that of a very elongate and rather flat ellipsoidal shuttle. 

 It may measure as much as -^jjj millim. Its substance consists of 

 an opaque slightly yellowish gangue, in which we see numerous 

 spherical corpuscles of nucleolar appearance. When, in consequence 

 of the crushing of the bodj , a fresh nucleus is placed directly in the 

 water, its substance contracts, and at the surface there appears a fine 

 structureless membrane, as in the case of many Infusoria. 



The body is traversed throughout its length by a long con- 

 tractile canal attached to the dorsal face, the pulsations of which, 

 from one systole to another, last a little more than a minute. This 

 canal is not rectilinear, but describes numerous sinuosities irregularly 

 disposed. Its diameter, in the state of diastole, is 1 ? ? millim. It 

 is furnished with proper walls and thus constitutes a true vessel. 

 In this character it differs from the contractile vacuoles of the other 

 Infusoria, which are only temporary cavities hollowed out in the 

 endosarc. The wall of the vessel, which is visible even in the living 

 animals, becomes still more apparent with coagulant reagents. This 

 vessel is moreover provided with orifices, which traverse the integu- 

 ment and open outwards in the form of very clearly visible pores in 

 the midst of the rows of cilia. These pores place the vessel in com- 

 munication with the external world, and serve for the issue of the 

 interior liquid at the moment of systole, and very probably for the 

 entrance of the exterior liquid during diastole. The pores, seven or 

 eight in number in large individuals, are placed exactly in a straight 

 line, at irregular distances on the course of the vessel. They are of 

 an oval form, and measure y$t& m ^im.. in length. 



This Infusory multiplies by dividing transversely into segments. 

 The segmentation is at first indicated at the middle of the length 

 of the body by a clear band in the endosarc. The nucleus divides 

 into two ; a constriction contracts the body at the point of segmen- 

 tation ; and the vessel becomes divided in two ; the two segments re- 

 main soldered together. Tbe same operation is then repeated at the 

 middle of each of the segments, so that we see four segments soldered 

 together ; then a second time at the middle of each of these four 

 segments, and the body is cut into eight segments still attached to 

 one another, and completely recalling, by their external aspect and 

 arrangement, the zoonites of the tapeworms. These segments 

 afterwards separate ; and one always finds many of them isolated in 

 the rectum of the hosts of this Infusory. 



This fine Infusory much resembles the Opalinid found by Von 

 Siebold in Planaria torva, and figured by Max Schultze under the 

 name of Opalina polymorplia. If we adopt the generic divisions 

 established by Stein in the family Opalinida3, it will have to take its 



