372 MONTGOMERY. [Vol. XV. 



large nucleolus, with a large vacuole ; he believes that subse- 

 quent to the two-nucleolus stage one of the nucleoli is extruded 

 from the nucleus. Two nucleoli were observed also in the ova 

 of AnipJiictcis, Satiytha, and Melinna. 



Flemming ('97) recurs to the controversy between Korschelt 

 ('96) and Meves ('97), and agrees with Meves that the macro- 

 somes are nucleoli, and the microsomes chromatin granules. 

 He also mentions the following observation on the ovum of 

 Ascidia canina : here there is one " Nucleolus " and one much 

 smaller " Kernkorper " ; " beobachtet man ihn [Kernkorper] 

 am lebend entnommenen Ei, so findet man ihn so gut wie 

 stets in Molekularbewegung, und zwar oft in recht grossen 

 Exkursionen." 



Hacker ('97a) ('96 is a preliminary communication), cleavage 

 stages of Cyclops brevicoriiis. This paper deals particularly with 

 the '*^intraspharale," " extranucleare," or " Aussen-Kornchen 

 (Ektosomen) " found in certain of the astrospheres of the 

 cleaving ovum. These ectosomes are small spherical bodies of 

 various size, which stain like the nucleoli, but somewhat more 

 intensely. In the resting stage of the cell there are several 

 nucleoli in the nucleus, and no ectosomes outside of it ; when 

 the nucleus enters on the aster stage, the nucleoli have disap- 

 peared and ectosomes are present in one of the astrospheres, 

 at first at the base of, subsequently on the whole periphery of, 

 the latter ; towards the close of the metakinesis there appear 

 in the place of the ectosomes larger clumps of red-staining 

 substance. He concludes : " So glaube ich es denn mit Sicher- 

 heit aussprechen zu diirfen, dass diese groberen Brocken auch 

 genetisch mit den Kornchen [Ektosomen] zusammenhangen, 

 sei es, dass sie direkte Umwandlungsprodukte derselben, sei es, 

 ■dass sie Neubildungen sind, welche dem namlichen Process 

 ihre Entstehung verdanken, aber in Folge der wahrend der 

 Theilung eintretenden Zustandsanderungen der Zelle eine etwas 

 andere Beschaffenheit, einen anderen Aggregatzustand ange- 

 nommen haben. Wie ich gleich hier hinzufiigen mochte, ver- 

 schwindet die Erscheinung, sowohl im Zweizellenstadium als in 

 den spateren Stadien, wahrend der eigentlichen Ruhepause 

 voUstandig, indem vermuthlich jene Massen einer Resorbtion 



