486 BULLETIN OF THE 



into the vitellus resembles the flow of a viscid liquid. The successive 

 forms assumed by this lengthened " body " vary greatly in different cases, 

 and change rapidly. It continues to diminish in size until there remains 

 only a filament presenting varicosities and surmounted by a motionless 

 cue. Some seconds later this latter has in turn disappeared, and one 

 sees in its place only a very pale elongated cone. This is an exudation 

 from the vitellus ; but the vibratile cilium (cue) in process of decom- 

 position may contribute to its formation. This " cone d'exsudation " 

 remains visible several minutes, and assumes the most diverse forms, 

 recalling the flames of a feu de paille, though not as rapid. Sometimes 

 it is simply conical ; sometimes nodulated and flanked by barbules and 

 tongues. Ic finally disappears (pp. 459, 460). The rays of the male 

 aster commence to be distinctly visible only some minutes after fecun- 

 dation, and then the clear spot is already advanced a little toward the 

 interior of the yolk. Some of the rays extend back to the surface 

 where the contact took place, and where a minute scar still remains. 

 Fol thinks 0. Hertwig has mistaken such rays for a part of the tail of a 

 spermatozoon. The female pronucleus commences to move toward the 

 male pronucleus only when it comes in contact with the rays of the 

 male aster (pp. 463, 464). 



Statements relating to the fecundation of the eggs of Heteropoda 

 are mentioned (p. 446) in connection with the review of their matu- 

 ration. 



BiscHOFF ('77, pp. 28 — 48) defends his theory of fecundation, as a 

 communicated molecular motion imparted by the spermatozoon to the egg, 

 from the misinterpretations which he holds it has suffered at the hands 

 of those critics who could see in it only a " Contactwirkung." A mate- 

 rial participation on the part of the spermatozoon does not appear to be 

 denied, but is valueless in the author's opinion to explain the actual 

 process of fecundation. ''Was aber die raumliche oder formbildende 

 Wirkung des Saamens bei der durch ihn auf das Ei iibertragenen Be- 

 wegung betrifFt, so ist diese an und fUr sich eine Thatsache, aber einst- 

 weilen eben nur eine Thatsache, fiir deren weitere Begriindung und 

 Erkenntniss bis jetzt auch nicht die mindeste Hofliiung besteht " 

 (p. 33). 



Apropos to a comparison of the ectoplasm and endoplasm of Protozoa 

 and eggs, Minot ('77^) calls attention to the theory that " the Rich- 

 tungsblaschen are comparable to the nucleoli of Infusoria. A further 

 confirmation of this homology is offered by the formation of the ' Kern- 

 spindel ' as introductory alike to the ejection of the direction cells and 



