CHROMOSOMES IN COREID HEMII'TKKA. IOC) 



j-ive in Archimerus, less complete in Anasa and Protenor). 

 Then- are n<> peculiar or "lagging" chromosomes in either of these 

 divisions. 



4. Tin- female pronucleus contains a group of chromosomes 

 similar in that borne 'by a spermatozoon having the "accessory 1 

 or i<lio< hromosome (directly proved in Archimerus). 



tilization the reduced groups from each pronucleus 

 an- -<-p. irately distinguishable and the chromosomes show the 

 -.inn -i/e relations as those of the spermatocyte and oocyte di\ i- 



I here are no nucleoli in either pronucleus. 



In tin- i leavage and early blastoderm nuclei of Archimerus, 



:elini(lfd and Protcnor, the chromosomes are pertectly 



ili-tim t ,m<l can IK- counted as readily as those in the gon.uls. 



T\\o i\pes of embryos are found, one having an odd and the 



niher .in even number of chromosomes, these numbers bein- 



re-pet ii\ely the same as occur in the spermatogonia and oogoni.i. 



A. ordingly it >eems fair to conclude that the former arc male-, 



the l.i 1 1 er females, and it thus becomes possible to distinguish 



tin sex "I an embryo by counting its chromosomes. 



7 Tin i< li< >rhromosomcs behave exactly like the other chromo- 

 v, .in.-, in i he oocyte divisions, at fertilization and in the cleavage 

 ami e.uK blasUxlerm stages. They never show any rcsemblan.v 

 t> iuitle.,li ami in Protcnor they can be identified in all sta 

 \\ iih al.- ilute certainty. 



li \\ill be >een that the results in general bear out the assump- 

 tion- ina.le by Stevens, Wilson and others regarding the number 

 .1111 1 bi-h.i\iir of the chromosomes in the maturation of the female 

 and in the somatic cells. They give additional morphological 

 support to theories of sex-production based upon the presence or 

 absence >f certain chromosomes and to the hypothesis of chronio- 

 some -intlix iduality or "genetic continuity of chromosomes" as 

 \\ il-on 'iwx) more cautiously calls it. 



\'. RKVIEW AND DISCUSSION. 



The literature on the maturation and early development of 

 the of in-ects and allied forms is very extensi\e. onering 



a period of over fifty years, but it is beyond the scope of the 

 pre-eiit paper to review it in detail except in so far as it concerns 



