86 PROFESSOR 0. BUTSCHLI. 



evenly distributed throughout the body, but, as in other 

 coloured Flagellata, there are found two pigment discs of 

 moderate thickness (fig. IT, a). These discs lie close 

 below the surface of the body, and are so closely approxi- 

 mated along the shorter and longer sides of the body that 

 only a small light space separates them (fig. 17, 5.) 



The vesicular nucleus, with its large inner body, lies at 

 the anterior boundary of the posterior third of the body ; in 

 dead specimens a thickened wall may be seen surrounding 

 the vesicle of the nucleus. The granules, which lie in a 

 double row in the interior of the body, consist mainly of 

 starch, as has been already shown by Schneider, although 

 many do not contain this substance. Iodine causes a blue 

 colouration in the starch granules, which disappears on the 

 addition of concentrated sulphuric acid, although there still 

 remains a considerable number of yellowish or reddish-brown 

 corpuscles. Sometimes in old specimens, starch appears to 

 be absent, and only a few small granules of high refractive 

 index fare present. In such cases the protoplasm of the 

 body is crowded with vacuoles, so that it appears to be 

 hollow and alveolar, without resulting injury to the 

 organism. One very remarkable observation has been 

 made by Biitschli. After treatment with acetic acid of 

 1 per cent, the appearance seen in fig. 17 g was obtained. 

 A number of fine rays shot out from the dead animal in all 

 directions, so that the appearance was like that of a Para- 

 msecium, in which all the trichocysts have been extruded. 

 Amongst the rays were here and there entangled a few 

 granular masses. The author puts forward, as an explana- 

 tion of this phenomenon, that the organisms have an arrange- 

 ment which is similar to the trichocysts of the Ciliata, 

 qualifying this, however, by the statement that no such 

 formation has yet been observed in the living organism. The 

 animals are very sensitive, and have been observed to die 

 rapidly under the cover glass ; their bodies becoming rounder 

 and rounder, and finally collapsing. Reproduction by longi- 

 tudinal fission has as yet been alone observed, as seen in 

 (fig. 17, d and f). In the single case observed by the 

 author, the flagella of the daughter individuals were present 

 before the pinching oif occurred, without their origin being 

 traced. The constriction occurs tolerably evenly along the 

 whole surface of the body (fig. 17, d), but probably some- 

 what earlier at the posterior extremity, since the products of 

 division remain joined for the longest period at the centre 

 of the body. In the pinched-off portion of the body, which 

 is tolerably transparent (fig. 17, d), are ^ number of dark 



