56 Mr. H. M. Bernard on the 



mass bound together by connective tissue. The walls of the 

 duct are bulged out to form what look like short branches, 

 but which are in reality only pocket-like outpushings. A 

 large nucleus lies in each pocket. 



The cells of the duct are no longer demonstrable as simple 

 cells ; their outermost portions are arranged in strands of 

 staining protoplasm and clear matter. Lankester has suggested 

 that these clear stria3 might be tubes ; but I think it more 

 probable that they are inflowing streams of the excretory 

 matter. This excretory matter, after passing through the 

 outer portions of ihe cells, seems to be absorbed by the nuclei, 

 which swell enormously and bulge out the wall of the duct 

 as above described. In this swollen state they no longer 

 take stain, but are large clear vesicles which are detached 

 into the lumen of the tube, where they finally break down. 

 Besides these enormous nuclei (21 /u. in long diameter), others 

 of all sizes are found, some comparatively small (12 /a), with 

 deeply-staining chromosomes. Altliough I have found no 

 traces of dividing nuclei — dividing /. e. in order to replace 

 those which are cast off — Lankester has a figure^ of thecoxal 

 gland of Buthus cyaneus in which the nuclei are obviously 

 dividing. Between the nuclei and the lumen of the tube there 

 is a very thin layer of staining and apparently undifferentiated 

 protoplasm. 



While in Scorpio the nuclei appear, as above described, to 

 absorb the excretory matter and to be cast off, in Galeoden 

 this matter is apparently collected in vacuoles of the cyto- 

 plasm, which are then detached and fill the lumen of the duct 

 with clear round vesicles. The detachment of the nuclei in 

 Scorjno has been mentioned by Lankester and Sturany; 

 but both seem doubtful whetlier this may not be due to the 

 preparation of the sections. Fig. 2, however, shows a portion 

 of tlie duct in which there are more detached nuclei in the 

 lumen of the duct than could have been derived from the 

 wall, where, indeed, the nuclei are still found in situ. Further, 

 the different character of the nuclei (the solid staining and 

 the large clear vesicular nuclei) seems to have escaped obser- 

 vation. The latter alone are found free in the lumen of the 

 duct. This remarkable function of the nuclei, as to the 

 correctness of which I think there can be little doubt, deserves 

 further investigation. 



This highly differentiated duct terminates, as is sometimes 

 the case in Galeodes, in a sponge-like system of branched 

 tubules. This mass of tubules does not, however, develop 

 freely among the tissues of the body as in Galeodes, but is 

 gathered together into a compact mass, round which the main 

 * Quart, Journ. Micr. Sci. xxiv. pi. xii. tig. 5. 



