320 DR. E. KLEIN. 



zone next this membrane unoccupied. But in all cases the 

 network is in connection ^ith what is known as the limiting 

 membrane by numerous fibrils. These connecting fibrils 

 appear naturally longer in those instances -where the intra- 

 nuclear network does not reach up to the nuclear membrane. 

 The network stains a pink colour; the colour is more pro- 

 nounced, ccetcris paribus, the more shrunk the network is, 

 but apart from this some portions of the network are stained 

 deeper than others. 



The fibrils of this network are highly refractive, and vary 

 in their thickness, course and arrangement. In some nuclei 

 they are delicate, fine, cylindrical and smooth, or stiff and 

 short, and so densely arranged as to leave more or less uniform 

 small spaces between them ; in others they are coarse, mem- 

 branous, and possessed of an irregular outline, are more or 

 less convoluted, and so arranged that the spaces formed by 

 their anastomoses are not uniform, bcino; sometimes larger 

 in the central parts of (he network tlian in the periphery, at 

 other times the reverse is the case. There arc nuclei in which 

 the fibres appear to possess a spiral or circular arrangement 

 in the periphery of the network. Seen from the narrower 

 side, some nuclei — especially those of the surface-epithe- 

 lium — show a chiefly longitudinal arrangement of the fibres 

 of the network. We find all forms between a network of 

 fibrils as represented, e.g. in a net, and a honeycoinb of mem- 

 branous structures, as represented in a sponge. In almost all 

 instances however, we observe a greater or smaller number 

 of minute bright spots, which as careful focussing proves 

 are fibrils of the network seen in optical transverse section 

 or at the point of anastomosis. Ijut it seems also that some 

 fibrils are possessed of irregular thickenings. This is shown 

 with remarkable clearness in those instances in which llie 

 nuclear membrane lias been broken at one or the other point 

 and the fibrils of the intranuclear network protrude through 

 this opening. In fig. 8, of Plate XVI, such protruding 

 fibrils are shown. Comparing the different nuclei one cannot 

 help noticing that the number of the above-named bright 

 dots is greater, the denser the network, the more convoluted 

 its fibrils are, or the more shrunk the network is as a whole. 



Numerous fragments of nuclei are met with in our pre- 

 parations ; these consist of greater or smaller portions of the 

 intranuclear network isolated from the nuclear membrane ; 

 in fig. 3, Plate XYI {a, h, c), may be seen such isolated net- 

 works. 



The nuclei of the cpitludial colls arc slightly flattened, and 

 when, therefore, seen in ])r(jfik>, they do not sho\v the net- 



