154 PROCEEDINGS OF THE ACADEMY OF ]PaRT I 



ules are dispersed. These instantly become red when treated with 

 carmine stain. The contractile vacuole is often encircled by a crown 

 of smaller vesicles, which after the systole will fill up the vacuole 

 again. It is at the anterior part of he body, and empties into a large 

 reservoir, which we must consider a little more at length. The fore- 

 part of the body terminates in a slight prominence, a very small point, 

 which itself borders the entranceof a very narrow tubular opening, this 

 tube then plunges straight down, to open into a vast pouch or reser- 

 voir. But, fromthe bottom of the reservoir, or rather a little higher up 

 on one of thesides, are seen arising two very short threads, one of which, 

 the longer, is directed upwards in a diagonal course and reaches 

 up to near the top of the reservoir, whilst the other, much shorter, 

 hardly reaches the middle. ^^ These two filaments, which must be 

 considered as two flagella that never extend any higher, each have 

 a basal granule, and the two granules, very near each other, some- 

 times appear enclosed in a common layer of very pure, bluish plasma. 

 This narrow bluish spot, however, is so indistinct that, doubting 

 its reality, I should not have mentioned it here, if de Beauchamp, 

 with whose observations I only became acquainted long after my 

 own were made, had not said that after the action of reagents he 

 found a small crescent-like black spot upon the wall of the principal 

 vacuole.'* 



Such is the structure of the body in these big specimens of Astasia. 

 But it may be added, that very large individuals, 80[j- in diameter 

 when in the spherical state, and SOO^jl when in full activity, are of 

 exceptional occurrence; they are mostly so large when only one in- 

 dividual inhabits the intestine of the Cyclops; more generally there 

 are two, four, eight or more individuals, in which cases they are smaller, 

 and it must be considered as probable that they all came from one 

 specimen, which divided and redivided inside the host. They are, in 

 fact, commonly of the same size in the same Cyclops and, if we have in 

 mind the extraordinary differences that are noticed between the 

 individuals one happens to meet with outside the hosts, we cannot but 

 recognize in this special uniformity in size the result of origin from 

 the same parent organism. 



^' The existence of rudimentary flagella does not seem to have been observed. 

 Alexieeff simply says of his Astasia that it presents a flagellum or has none; 

 and de Beauchamp that "sometimes a flagellum is present, but in most cases 

 it is impossible to find any trace of one." Neither of these authors, however, 

 has seen anything inside the reservoir, and de Beauchamp speaks of the flagellum 

 as taking its origin — when present at all — from the entrance to the buccal tube. 



1^ It is not impossible that Pascher considered de Beauchamp's black spot 

 as a rudimentary stigma, for in the diagnosis of that species he says: "Stigma 

 rudimentary, on the principal vacuole." But de Beauchamp certainly did not 

 see it in this light, as he expressly declares he did not find any trace of a stigma. 



