334 BULLETIN OF THE 



ded in the viscid substance of tiie nucleus are themselves viscid, they 

 will be drawn out into filaments with thickenings at one end or in the 

 middle according as the traction is from one or both sides. Thus it 

 happens in the division of the sperm mother-cells of Strongylus auricu- 

 laris that the nucleoli, arranged in rows, are converted by this stretching 

 into meridional fibres; but if the numerous spherules are movahly im- 

 bedded in the viscid matrix, then an elongation of the latter will cause 

 the former to arrange themselves in parallel rows, which will give origin 

 to a striate appearance. 



Grobben (78, p. 38, Taf. III. Fig. 17) has often seen the spindle- 

 shaped nucleus with fibres and prominent equatorial thickenings in the 

 large testis cells of Astacus. 



In his paper on the organization and development of the Oxyuridse, 

 Galeb (78") has given an account of the nucleus during segmentation. 

 In Oxyuris blatticola (p. 365) one finds eggs in the following conditions : 

 non-segmented eggs with a germinative vesicle [primary segmentation 

 nucleus?] near one of the poles (PL XXII. Fig. 1) ; others with the germi- 

 native vesicle elongated into the shape of a biscuit and in process of 

 division (PL XXII. Fig. 2). Subsequently the germinative vesicle di- 

 vides, and one then sees two vaguely rounded clear spots in the vitellus. 

 The figure cited (PL XXII. Fig. 3) represents each of the spots as 

 embracing a single nucleolus. The segmentation follows rapidly, and the 

 halves of the " germinative vesicle" separate, the larger portion migrating 

 to the opposite pole of the Q^g. The inequality in the size of the first 

 two segmentation spheres may be attributed (p. 366) to this inequality 

 in the size of the segments of the germinative vesicle ; each portion of 

 the latter probably exercising an attractive force upon the vitelline 

 granules proportional to its volume. Although the author has seen the 

 stellate figures in the eggs of other animals, he has never succeeded in 

 doing so here, and concludes that they are concealed by transparent 

 fatty vesicles, unless, however, their production is caused by the em- 

 ployment of reagents. In fact something of this radial structure was 

 seen after using reagents in the case of 0. Kiinckeli. Of a spindle 

 metamorphosis of the nucleus, the author may be said to have seen 

 nothing. 



In the last chapter of his book, " Ueber das Ei," etc., Brandt (78) 

 argues further to show that the supposed disappearance of the ger- 

 minative vesicle (and of the nucleus during segmentation) is due to 

 the active amoeboid changes of its form. " Die Theilung des Keim- 

 blaschens, sowie die der Furchungskerne, vollzieht sich unt3r wech- 



