146 proceed'ings of the academy of [Part I 



to note, in comparison with Cryptomonas curvata where they never 

 exist. Very near the anterior extremity, and under the dorsal 

 prominence, is a very distinct contractile vacuole, which collapses 

 about every half minute, slowly to fill up again. The nucleus, 

 lying in the posterior region, is round, very large, very clear, and 

 has a small central caryosom. Around the nucleus is clear, pure 

 protoplasm, in which are dispersed shining globules of an extremely 

 small size, whose appearance is that of leucosine. The two flagella 

 are seen to start from the base of that beak-like prolongation that 

 terminates the dorsal side of the body, but they arise nearer the 

 ventral than the dorsal side, that is to say, on the ventral wall of 

 that deep cavity which has been erroneously called the pharynx. 

 When the little organism is swimming, nothing can be seen of the 

 flagella; at rest, one of them is generally seen rolled into a wide curve, 

 on the ventral side of the body the other extending backward, on 

 the dorsal side. In one single instance, and in a very much com- 

 pressed individual, whose body was spread into a broad layer, I 

 was able to detect a very small basal granule. The pharynx is a 

 deep, tubular or, more exactly, fusiform fossa, which plunges into 

 the body down to the middle of its length, and even sometimes 

 lower. At its lower end, this cavity is conical; near the upper end it 

 narrows to a tube, then again somewhat expands, and opens funnel- 

 like to the exterior. It is now seen to be carpeted, all along its 

 inner wall, by a continuous sheet of clear granules, in one single 

 layer and in perfect setting, disposed in such a manner that the eye 

 can divide the surface either in longitudinal or in diagonal parallel 

 lines, in two series crossing each other (somewhat like the appear- 

 ance of the shell in Arcella or, better, Cyphoderia?^ In reality, 

 these small granules or pearls are disposed along diagonal lines 

 going from left to right and from above below, and constitute a 

 kind of ''cage" whose lower end reaches far down into the pit, and 

 whose anterior end suddenly terminates in a broad truncature. 

 The number of the diagonal rows may be counted (in big specimens 

 at least) as sixteen, and each row comprises about the same number 

 of pearls also, so that we arrive to a total number of 256 pearls. 

 The cage, however, if my observations are right, is not absolutely 

 continuous; it seems to be split on one of its sides, the dorsal one, 

 and from end to end, one of the borders of the longitudinal fissure 

 being somewhat incurved; the whole cage, in fact, might be com- 

 pared to an enrolled leaf, whose edges do not completely join. The 

 layer of pearls, as we said before, carpets the inside of the pit, but 

 the actual form of the pit is not easy to determine; it is neither a 

 tube nor a fusiform cavity. Could we suppose, for instance, liquid 

 plaster to be cast into the fossa and then removed in the hardened 



^^Belar (4) gives these grains, in Chilomonas 'paramaeciwn, as forming 8 

 longitudinal rows, with 10-16 grains for each row. In Cryptomonas ovata, 

 which dilifers from Chilomonas only in the possession of chromatophores, the 

 grains are more numerous, and the rows also. 



