^28 The Oogenesis of the Tortoise 



rents or whatever else it may be, sometimes leave a track or channel 

 behind, in which the granules of the matrix are scarce or almost absent. 

 Consequently the cytoreticulum is especially distinct. I do not know 

 how to designate this effect except by the rather awkward term plasma 

 channel. 



These channels are rarely straight ; they turn and twist in every direc- 

 tion. Consequently a longitudinal section of such a channel is rare. 

 In Plate II, Fig. 31, is represented a plasma channel in the form of a 

 long, bent and twisted body with an enlargement at each end. Another 

 is represented in Plate IV, Pig. 68. If the granular substance of which 

 this is composed should all flow toward one end, it would leave a tem- 

 porary track in which the cytoreticulum would be evident. I take it 

 that such a transfer of granular matrix actually takes place. Cases can 

 be found where both longitudinal but more frequently transverse sections 

 of such channels occur. Such an one is very evident in Plate VI, Fig. 

 78. The material having thus flown together would form a more or 

 less spherical body, as appears in Plate IV, Fig. 66; Plate VI, Fig. 80, 

 and Plate III, Fig. 54; Plate I, Fig. 23; Plate II, Fig. 37. It is evi- 

 dent from these figures, also, that several such spherical masses often 

 exist in the neighborhood of the cytocenter (Plate I, Fig. 23; Plate II, 

 Figs. 30, 37; Plate III, Fig. 54, etc.) 



Plasma Channel. — Most interesting facts to me have been such ap- 

 pearances as those represented in Plate V, Figs. 72, 73, 74, serial sections 

 of the same egg, where the plasma channel is actually continuous with 

 the germinal vesicle. These figures are not at all exaggerated, incredible 

 as it may seem. The channel is round in section. The very distinct 

 cytoreticulum within this channel is certainly, so far as can be seen, 

 directly continuous with the contents of the germinal vesicle. At the 

 bottom of this channel the granular mass has accumulated, apparently 

 while flowing out from the germinal vesicle and afterward divided into 

 several currents. In Plate VI, Fig. 81, is another, somewhat elongated 

 form, drawn from reconstruction of serial sections. In the different 

 sections the granular mass forms a ring around the oval open space as is 

 indicated in the drawing. This has been seen in other sections also. 

 Most of the material here, it will be noticed, has become scattered in 

 small, irregular bodies throughout the cytocoel, several such bodies also 

 appearing close to the germinal vesicle. 



A comparison of Plate V, Figs. 72, 73, 74, and Plate VI, Fig. 81, 

 with Plate VI, Fig. 83, suggests that the latter is similar to the former, 

 in that it is more or less spherical, and is, to all appearances, connected 

 with the germinal vesicle. In this case, however, the granular substance 



