THE EARLY DEVELOPMENT OF THE MAESUPIALIA. 63 



cell-bodies from which thej arise. Attention may be specially 

 directed to the cell towards the left of the figure (marked ent.). 

 Here we have an entodermal cell whose cytoplasmic body is 

 evidently still partially intercalated between the cellsof the wall, 

 but which is, at the same time, prolonged inwards (towards 

 the left) so as to underlie the adjoining ectodermal cell. 

 From this inward prolongation there are given off two slender 

 processes, one short and tapering, the other very much 

 longer ; this latter, after becoming very attenuated, gradually 

 widens to form an irregular fan-shaped expansion, sucker- 

 like in appearance, and produced into several slender 

 threads, which is situated adjacent to the nucleus of 

 the ectodermal cell on the extreme left. Then from the 

 right side of the same cell there is given off a small inwardly 

 projecting bulbous lobe which may well be the start of just 

 such another process as arises from the left side. Processes 

 of the peculiar sucker-like type just described, formed of a 

 slender elongated stem and a distal expanded extremity from 

 which delicate filamentous prolongations are g*iven off, are 

 abundantly met with in preparations, and strikingly recall the 

 pseudopodia of various Rhizopoda. They are seen in con- 

 nection Avith other entodermal cells in fig. 70, and with many 

 of those in fig. 68. I regard them as veritable pseudopodia. 

 Towards the right side of fig. 70 the two entodermal cells 

 there situated stand in direct protoplasmic continuity by 

 means of two slender connecting threads, whilst the upper of 

 these two cells is again joined by a very fine process to the 

 irregular pseudopodial expansion which arises from one of 

 the two entodermal cells situated nearer the middle of the 

 figure, and that same expansion is directly connected with the 

 second of the two entodermal cells just mentioned, so that we 

 have here established the beginning of a cell-network, prior 

 to the complete emancipation of its constituent entodermal 

 elements from the unilaminar wall. We have, then, clear 

 evidence that the entodermal elements in Dasyurus, prior to 

 their separation from the unilaminar formative region are 

 capable of exhibiting amoeboid activity, since not only may 



