126 PROCEEDINGS OF THE ACADEMY OF [PaRT J 



cell, very likely in the same manner as will be described in the next 

 species; but I could not follow the events to the end, owing to the 

 animalcule being lost by accident. 



But such a division into equal parts is not the only one that can 

 be observed. I happened twice to meet with quite another process. 

 Instead of an equal transverse division of the individual, a very 

 small portion only was seen to detach; first a Httle bud (Plate VI, 

 fig. 25, a) at the anterior end of the body, then (Plate VI, fig. 25, h), 

 after complete separation, a spherical little being was formed, hardly 

 5[i in diameter, with a long flagellum and a normal contractile vesicle ; 

 then it lengthened into a little flagellate, whose small size was the 

 only character to distinguish it from the normal individuals. I 

 could not, however, follow the little swimming organisms very 

 far, and cannot suggest any explanation of the phenomena. Per- 

 haps the cases were purely pathological. 



Encystment was often observed.^ The body becomes a yellow- 

 ish olivet green, then a golden yellow, and finally brown; a mem- 

 brane has gradually been secreted, which grows finally very thick; 

 at first it is transparent enough to allow of the contractile vesicle 

 to be distinctly seen, but finally it looks quite opaque. A very 

 curious fact which remains to be noted (Plate VI, fig. 26) is that 

 up to the completion of the construction of the cyst, the anterior 

 part is open, and from the opening are seen still protruding either 

 the collar or both the collar and the flagellum. Only when the 

 construction is entirely finished, these plasmatic appendages 

 begin to retreat, disappearing in the cyst itself; this latter, then, 

 is seen to be cylindrical, or somewhat swollen in the middle (Plate 

 VI, fig. 27), and may be compared to a cannon shell, provided 

 anteriorly with a circular opening, which also, however, will soon 

 be shut. Old cysts, in fact, generally have no opening, yet some- 

 times an anterior aperture is visible, but in empty cysts only, 

 whose contents have very likely been liberated. 



The encystment takes place inside the capsule, yet sometimes 

 cysts are met with which are completely free from any surrounding 

 envelope, and, besides, are provided with a short yellowish stem 

 attaching them to the jelly. The fact might perhaps be explained 



^ Lemmermann (27), in his diagnosis of the genus Salpingoeca, speaks of the 

 cysts in the following terms: "Cysts inside the capsule spherical or oval, with 

 a thin membrane or naked." My observations on Salpmgoeca polygonatum 

 are such as to furnish us with new or different data. 



