Artificial Parthenogenesis and Heredity 293 



only, that a living spermatozoon carries the parthenogenetic 

 substances into the egg. The character of these plutei is 

 always the same; they do not show any such variations as 

 Tennent reports. 



In addition to fertilizing the eggs of S. purpuratus with the 

 sperm of starfish, the writer succeeded also in fertilizing the 

 eggs of purpuratus with the sperm of ophiurids and holothurians. 

 Godlewski used the same method with success for the fertiliza- 

 tion of the egg of the sea-urchin with the sperm of a crinoid 

 (Antedon). In all these cases the larvae were purely maternal.' 



Mg. 84 Pig. 85 Fig. 86 



Pigs. 84r-86. — Pive-days-old piutei of S. purpuratus S and S. franciacanua i. 

 Tlie plutei are different from the parthenogenetic plutei. 



Godlewski found that the nuclei of crinoid and sea-urchin 

 fuse. The chromosomes of Antedon are found in the nuclei of 

 the sea-urchin egg fertilized with Antedon sperm. The eggs 

 developed normally to the blastula stage, when a retardation 

 and other abnormalities ensued. Very few plutei were obtained. 

 The results of Godlewski were fully confirmed by Baltzer.^ 

 The skeleton was as in Godlewski's experiments purely maternal. 

 He confirms the result of Godlfewski, that in spite of the par- 

 ticipation of the paternal chromosomes in the development no 

 transmission of hereditary characters can be observed. 



'Godlewski, " Untersuchungen ueber die Bastardlerung der Echinoiden- 

 und Crinoiden-familie," Archiv /. Entwicklungamechanik, XX, 579, 1906; Daa 

 Vererbungsproblem im Lichte der Entwicklungsmechanik betrachtet, Leipzig, 1909. 



' Baltzer, "Ueber die Beziehung zwischen dem Chromatin und der Entwick" 

 lung der Vererbungsrichtung bei Echinodermenbastarden," Arch. f. Zellforschg., 

 V, 497, 1910. 



