CHROMOSOMES OF HIPPOXOE AND MOIRA. 169 



pair. In all <>1 the eggs tin- -oinati;: number of chronio-omt 

 iht- -.uiic; /. c., thin y->ix. In accordance with previou- con- 

 clusion- upon the occurrence of the heterochromo-< .me- in in-cct-. 

 the dimorphism in the chromosome groups of Strongylocentrotus 

 i- correlated with the dimorphi-m of ^e\ in cchinodenn>. H<>\\ - 



r, Ba!t/er, trom hi- "1 -ervation- on Echinus eggs Ci 

 lenili/ed with Strongylocentrotus s])erm. to-ether with observa- 

 tions on nuiltipolar -pindle- in di-pern. < ggs, conclude- ihat the 

 odd hook i- originally pre-ent in the e.y.u. In-tead of l\\o kind- 



perm as, we know. e\i-t in tin- in-rrt-. in ihe i-chinoderm- tlu-rc 



tWO kind- Po QUOti from \\'il-..n. "lO, "il i- ihe 



Ifinalc thai i- the lit' ullile the male i- llonio- 



in-odui lion in th,-r aiiim.il- mn-i then-Ion- 

 <-oiiform to iht- lorinu! 



:oan (/ /'(!. l-\-male. 

 .-. Male." 



I - inn nt has obtained evidence which, 1 think, shows thai thi 



loMimla^ d<> not ho|<l for all echin 'drnn-. An .n-ioiini of hi- 

 int<-n--tin^ ob i\ Ltions a -l-i-uhi-rr in thi- journal. 



In Echinus, \\hirh al-o (oiiiain- lhirt\--i\ hromo-onu--, ihe 



urrence ! ilmt ; ristic pair- \\ iMi-hnl ; \i/ 



pair o| lar^r hooks, a -mall hor-t ---hoc or \'--h.tpcd chro- 



niii-omi- and a pair o| \-r\ li \ -mall \'--hapt-d un- 



paired chromosome is also found in one hall o* t lh \\ Inch 



corresponds to the unpaired hook ii .'rot us. 



In a lalrr paper, 'lO, I'.ah/i i dt - lilu-- fliaraclt-ri-lit elrmt-nl- 

 in the chromosome groups :nnl<in> and .1 rhm'in 



pustulosa. riirimnil" matic chromosomes in ^ 'I'liinns 



i- toi i\ -two. All are rod --h aped. T\\o -omalie pair- could ln-u - 

 c\t-r l>e di-tin;cui-hcil in all of tin . ggs \>\ reason of tlu-ir exi 

 sive length-. \ ..... hi chrt>mo-ome could I >e demon-trated in thi- 

 -|n-( it-- dm-, no doiil't. to tin- lack of difterent iat imi in form of the 

 mi nil M -i- of i he -rou|). . ! -h. '\\eil a numlier of -mall hook- 



and I --ha]>ed chromo-oiiie- hut the nnla\ oral >le nature of the 

 pre\ciited detailed -tud\ . The -omalic mi ml H r i- forl\ . The 

 c-hromo-ome- in thi- species n--einl>lc tlue ol Arbacia fuim'tnldtii 

 li;^nred l.y Ten in n' . '07. in that the\ a \\ hole Comparatively 



short. 



