142 PROCEEDINGS OF THE ACADEMY OF [PaRT 1 



born concerning the fixation of these Flagellates: "While in Dino- 

 bryon the younger cells are set inside the inner border of the old 

 ones, in Hyalobryon it is the outside wall that is chosen as a point of 

 fixation, and this point is very far from the aperture." Now there 

 seems to be here some misunderstanding , Lauterborn is here speaking 

 of the fixation as quite a different thing from the "lines of growth," 

 which latter would in his opinion point to a single individual build- 

 ing a formal row of rings above each other, while according to my 

 observations there are no "lines of growth" at all, but the animal- 

 cules would settle down in two different ways: either inside empty 

 tubes, as we just described, or outside and generally very far away 

 from the opening, these latter individuals would enlarge the colony 

 in size and breadth, the former would only lengthen the existing 

 tubes. 



The second way, by simple juxtaposition, is by far the more fre- 

 quent of the two (atleastitwasatPinchat), and colonies are formed, 

 whose appearance is very curious and variable, now it is a branching 

 thicket, now the tubes seem to start from a single point (Plate VIII, 

 figs. 51, 52), now they are parallel to each other, now straight or 

 very often in a contorted bundle (Plate VIII, fig. 52). 



The small inhabitant of the tube is indeed of a very timid nature, 

 and leaves its tube at the first appearance of danger, the very trans- 

 portation of a colony from the general collection to an excavated 

 slide for purpose of better observation is enough to cause more 

 than half its members to escape during the journey, and those which 

 still are left also very soon take to flight. It is quite probable that 

 the animalcules are just as ready to settle down as they are to leave, 

 and empty bundles of tubes may very well get the preference, they 

 then affix themselves either against or inside the tubes, but in this 

 latter case quite near the opening, and according to the conditions 

 the changes may be of such frequency that after a time a formal set 

 of rings are seen one behind the other. 



As for the tubes themselves, whose length may reach as much as 

 150[JL (Lauterborn speaks of 55[j.) for only 5 or &\i. in breadth, they 

 are perfectly colorless, and "for an exact study it is necessary to 

 have recourse to staining, which does not present any difficulty, 

 as they very quickly absorb aniline colors" (Lauterborn). I may 

 add that Dahlia tincture instantly colors the tubes a very fine peach- 

 blossom tint, but this lasts only for a moment. 



The Flagellate, 18[ji, in length and 3 or 4 in breadth, is spindle- 

 shaped, with at its anterior extremity a short beak-like prolonga- 



