DENDROOOMETES PAllADOXUS. 361 



PLATE 18. 



1. Section tlirougli one of a pair of conjugates after tiie second division 

 of tlie segmentation nuclei (Stage J), showing one nucleus (n, M.) sligiitly 

 larger (5 ft) than the otlier three (4 fi). This larger nucleus becomes the new 

 meganucleus. No. 122. 



2. The new meganucleus from the last figure enlarged to show that the 

 chromatin is at this stage in the form of a coarse skein lying in the centre 

 of a clear sjiace. 



3. The new meganucleus at a later stage. It is now about S /x in diameter. 

 A considerable quantity of the chromatin has now collected at the periphery, 

 and some of it a|)pears to be escaping into the cytoplasm. No. 145. 



4. New meganucleus at a slill later stage, 10 /i in diameter. Darkly 

 staining granules of chromatin are now seen at the periphery, one or two 

 witiiin the periphery, but the central parts stain very faintly indeed. Series 

 131. 



5. New meganucleus at a still later stage, 12 fx in diameter, containing 

 numerous evenly distributed granules of chromatin. Slide 131. 



6. Section through a pair of conjugates showing the approach of the old 

 meganuclei (M.) to each other at the bar of junction. No. 52. (Tiie micro- 

 nuclei were not clearly stained in this preparation, and are consequently 

 entirely omitted from the drawing.) 



7. Section through a pair of conjugates (Stage J), showing one meganucleus 

 at the limiting membrane, the other pointing towards it but not reaching it. 

 There is one new meganucleus and three micronuclei rei)resented in each. (In 

 the preparation, owing to an unfortunate tear, only one micronucleus can be 

 actually seen in the lower conjugate.) No. 141. 



8. Section through a pair of conjugates (Stage J), showing the approach of 

 the old meganuclei to each other at the limiliiig membrane. In each of 

 these there is one new meganucleus and five micronuclei (an exceptional 

 condition). In the cytoplasm of the lower conjugate there may be seen three 

 granules of chromatin (?). These may be the remnants of the polar nuclei. 

 Slide 131. 



9. A small portion of the old meganucleus of one of the conjugates of 

 the last preparation more highly magnified, showing the chromatin arranged 

 in irregular parallel lines with thickened nodes and lumps. 



10. Section through a resting meganucleus, stained by iron-hsematoxylin. 

 No membrana liinitans can be seen. No. 255. 



11. Section through the conjugative processes of a pair of Dendrocometes, 

 showing the organic fusion of the two meganuclei in Stage J. No. 98 S. 



12. Section through the conjugative processes of a pair of Dendrocometes 



