248 BULLETIN OF THE 



this view seems to be corroborated by the explanation (p. xxviii.) of the 

 figure, viz. : " Fig. 2. s, Die Scheidewand ; ini oberen Theile des Eies zeigt 

 sie graue radiale Streifen." Also in the explanation (p. xxix.) of Fig. 7 a 

 (same plate) : " x, einer an beiden Eihiilften sichtbaren weissen Bruchflache, an 

 deren Peripherie die Scheidewand ahnliche radiare Streifen wie bei Fig. 2. 

 darbeitet." If the rays were thus superficial, as Kemak implies, they could 

 hardly be considered as belonging to a real protoplasmic aster. 



It is quite another question whether Remak was right as to the location of 

 the " Streifen," — whether they may not, after all, have belonged to the deep por- 

 tions of the protoplasm. 



An examination of the figures which O. Hertwig ('77, Taf. IV., V.) gives of 

 the radiate appearances in diff'erent stages of the eggs of Rana temporaria fur- 

 nishes nothing which would warrant us in referring the figures of Remak to 

 like phenomena. It seems to me that the peculiarities which Remak has 

 figured may perhaps be due to variations in the thickness of the [thin] pig- 

 ment-lamella which, according to Hertwig (op. cit., p. 49, foot-note), sinks down 

 into the yolk at cleavage. Unfortunately Hertwig gives only a profile view 

 (Taf. V. Fig. 6) of this lamella, from which it is not possible to determine 

 whether its thickness is subject to alternations capable of producing, as sug- 

 gested, this radiate eff'ect. 



Meissner ('56, pp. 374, 375), writing of Echinus, says : " Das Keimblaschen 

 ist in zur Ausstossung reifen Eier bereits verschwunden ; die Dotterkornchen 

 zeigen eine sehr deutliche radiare Gruppirung um ein belles Centrum, welches 



sich als ein rothlicher, zahfliissiger Tropfen isoliren lasst Der die Stelle 



eines Kerns vertretende rothiiche zahfliissige Tropfen, der oben erwiihnt wurde, 

 theilt sich und der Dotter sondert sich in zwei Massen, deren jede sich um ein 

 Centrum wieder radiar gruppirt." 



The following year Gegenbaur ('57, p. 7, Fig. 3) described similar appear- 

 ances during the first and second segmentations of the egg of Sagitta. A little 

 while after the segmentation has been accomplished, the fine molecules of the 

 yolk each time appear collected in a greater abundance around the nucleus, 

 forming radial streaks (Streifen), which gradually disappear toward the pe- 

 riphery. 



Further observations on the sperm-cells of Nematodes were made by Munk, 

 Walter, and Claparede. 



Munk ('58, pp. 382-391, Taf. XV. Figs. 11-14, 25, etc.) figures the structure 

 in question for both parent and daughter cells. The " strahlige Anordnung " 

 was observed in Ascaris mystax, A. marginata, and A. megalocephala (p. 382). 

 In the formation of the four daughter cells, " The clear central nucleus of the 

 radiate cell vanishes, and there appear nearer the periphery two new clear 

 places, each of which becomes again the centre of a radial arrangement of the 

 granules." Then follows the division of the cell. This process is then repeated 

 on each of the new cells in like manner. When the four daughter cells have 

 become free, the "strahlige Anordnung" of the granules soon disappears, and 

 needle-shaped granules are no longer to be seen. 



