a. Ikkno 55 



nf pureli/ maienuil tt/fte (VoriKm, IltThst, Ku|N'IwicH<*r. (t(Kll(»\vHki jun., 

 Biiltzor, Morgiin. etc. vie). CyUAof^\ci\\ invrstij^iitidnH of thenf falHc* 

 hybrids won* mmlo iils<> by niftny aii thorn. The fiict hjw Ixm'ii n'VfnlcKl 

 that in the hybriciisatitm of th«' Iv-hinoids thr s|MTiiiat<ozoH jilwayH mU'r 

 thf ogg-ryUiplitsin. 'V\\v behaviour of th«' .s|H'nn-nMclruM wjis ho\vrvj«r 

 foiiml always nt>t t^» be tht» winie. For iiistaiiee, in Homr nxm'H (as 

 Kchiims J x Mi/tihis^, Stroiuft/locentrotns J :•; }fi/tilns ^) th«* r^^- aii<i 

 the sjK»rin-inieK'i do not come to real fusion, and the latter undrr^o 

 ^nulual de)(i'neration (Kupelwieser') ; in many other <";ts«s l>oth nuelri 

 ftise U) each other, and in later stages the paternal ehroniatin is 

 ebniinat^Hl in s<)nie way (Haltzer'. Kupelwicscr^ (i<Kll«'wski jun.*). 

 Acconlin); t«» Baltzer'. in the hybrid Sphaerec/nnus J x StrotHfi/htren- 

 tnitus (fy which is intt'rnu'diate between the two pan*nts, n<» ehroiuatin 

 elimination takes place, whilst in S(ron(/iflocentn>tus ? x Sp}i(U'rechiitiiH(^ , 

 which is of purely maternal typ<', he w;us able to ob.serve the elimination 

 of pit-ernal chromatin during the fiixt cleavage. 



On the contnirv, in the hybrid Echinus J x Antedon </, which is of 

 purely maternal ty|K', an<l where also the sperm- and egg-iniclei fuse 

 with eivch other, no eliminati«ui of paternal chromatin w;vs obsi*rved 

 (Goillewski jun.'') ; the latter authoi- has also observed that the chromo- 

 somes deriveil both from the egg- and the sperm -nuclei participate 

 in the first mitosis of the Qgg (fii*st cleavage), though he could not 

 there distinguish paternal and maternal chromosomes from each other. 

 Biiltzer", who confirms in general the statement of Godlewski jun,, was 

 able even to distinguish both kinds of chromosomes. The results of 

 the cj'tological studies of Sti-asburger on Fracjaria above cited are 

 thus in exact accordance with this discovery of Godlew.ski jun. and 

 Baltzer on Echinus x Antedon, because in both cases no elimination of 

 p{\ternal chromatin succeeding the fusion of the two nuclei does take 

 place. What cytological phenomena will occur in the formation of false 

 hybrids of Saluc should be one of the objects of our future study. 



* Archil' f. Enticicklungsviechanik der Organismeu, Bd xxvii. 190l>, pp. 134—462. 

 » Archivf. Zelljorschung, Bd v. 1910, pp. 497—621. 



' Ibid. Bd VIII. 1912, pp. 352—395. 



* Archivf. KntwicklungKinechanik, Bd xxxiii. 1912, pp. 196—254. 

 » L.C. 



* Archil- f. Kntirickhnigsmechanik. Bd xx. 1906, pp. 574—643. 

 ' L.c. 



