1921] NATURAL SCIENCES OF PHILADELPHIA. 113 



two parts, the first of which entered the body of the Dimorpha; 

 the second fragment then divided again, and finally each of the 

 separated portions got into the Dimorpha and quickly rounded 

 itself into a small pellet. Our Dimorpha seemed in fact to feed 

 exclusively on this little Infusorian, and proved excessively glutton- 

 ous. Three minutes are sufficient for the conversion of a living 

 Bolanitozoon into a number of pellets inside the Dimorpha, and this 

 latter, which measured at first say about 30[x in diameter, increases 

 to 40[JL in diameter after the capture. 



We must now consider the flagella somewhat at length. In a 

 Dimorpha favorably oriented for good observation, one can dis- 

 tinguish in the body an anterior part, sKghtly flattened, and even 

 sometimes depressed to form a shallow median cup, and from that 

 cup arise four very fine threads, hardly visible, about twice the 

 length of the body; they appear and suddenly disappear, and when 

 lost are very difficult to trace again, owing to their extraordinary 

 tenuity. Two of them are often seen to cross each other at a short 

 distance from their base, which fact is due to their being in pairs, 

 one of the pairs originating left and the other right of a central 

 point of fixation (Plate V, fig. 4) . 



Gruber could not ascertain the presence of a nucleus, at least 

 in the hving animalcule, but says he easily demonstrated it with 

 reagents. Blochmann, however, and afterwards Schouteden (31), 

 each gave a rather complete description of what they considers a 

 the nuclear apparatus, and it is interesting to quote what the latter 

 of these observers ^vi-ites upon the subject: "The nucleus is already 

 visible in the living animal, more or less distinctly according to 

 the individuals. But it is easy to make it appear by kilhng the 

 organism with a solution of picric acid, which colors the nucleus 

 yellow. One sees then that chormatin is united in a thick mass 

 which in optical section appears like a crescent with more or less 

 rounded or obtuse points; really this mass constitutes something 

 like a hemisphere (or segmont of a sphere, smaller or sometimes 

 larger,) hollow but with a thick wall. 



''Inside that peculiar mass, in the cavity which it surrounds, 

 one sees the axial threads of the pseudopodia, which pass through 

 the body, to converge toward the same point, namely to a shining, 

 very distinct granule, which is indeed already visible, with some 

 attention, in the living animal. In this same place, besides, is the 

 insertion of the flagella, which diverge from the common point 

 inside the plasma and come out of the body in two distinctly sepa- 

 rated regions .... Blochmann was rather puzzled by the fact that the 

 axial threads of the pseudopodia thus converge through the nucleus 



