316 Dr. A. Gruber on Protozoa. 



water such sources of oxygen will of course be preferently 

 sought by the Infusoria. This would also explain why the 

 colonies form hollow spheres. The Flagellata may have 

 constructed their tubes from the periphery of the air- vesicle 

 outwards, and subsequently the air in the interior may have 

 disappeared. Besides the settlements constituted as above, 

 there were also very frequently unions of only a very few 

 individuals ; and in these no indications of the tubes were to 



be observed. 



The Infusoria themselves do not differ from the species 

 allied to them. Generally the body, which measures O01- 

 0*015 mil Km., is globular; but it may assume a more oval 

 form. Imbedded in the granular protoplasm are the vacuoles 

 and nucleus, which latter is not visible in the living animal, 

 but becomes very distinct by staining with carmine solution. 

 Lastly, at the anterior end of the body arise the llagella, two 

 in number, as is the character of the genus Spongomonas. 



2. The Genus Stichotricha. 



\Vhile most of the hypotrichous Infusoria have not the 

 habit of secreting a protective envelope around their bodies, 

 we find in one genus of this section such a practice fully de- 

 veloped, namely in the genus Stichotricha. The other 

 Hypotricha, indeed, can very well dispense with any protec- 

 tive arrangement, as they usually possess a firm, often cara- 

 pace-like cortical layer ; but this is not the case in Sticho- 

 tricha, in which the body is extremely soft and flexible. 

 Under the name of Stichotricha socialis I formerly made 

 known a form* which constructs dendritically branched tubes, 

 while Stein f has figured and described Stichotricha sccunda, 

 which is possibly only a variety of the above species, and 

 which lives solitary, and constructs a somewhat flask-shaped 

 carapace rounded at the bottom. I have since observed other 

 forms of carapace- and colony-construction in Stichotricha ) 

 and these I would now describe. 



_ I may remark that to two of these Infusoria I have not 

 given new names, because I cannot say with certainty whether 

 they are distinct species or only varieties of the same species. 

 This applies especially to one form which was coloured green 

 by the presence of chlorophyll-corpuscles J. This Sticho- 



* " Neue Infusorien," Zeitschr. fur wiss. ZooL xxxiii. 



t Der Organisms der Infusionsthiere, Bd. i. 



X I say cMoropbyll-corpiiscks without in any wav wishing to decide 



whether we have to do here with true chlorophyll-corpuscle, or, accoiding 



to Brandt and tntz (Biol. Centralbl. Bd. i. pp. 524 and '040), with uni- 

 cellular Algse. 



