PMENT OF Tin: rWO HIDD1 



127 



tin- embrvnnic arra ha- a uined all ov:il form, tin- opacity a' 



riur mil, ir the terminal ridire (li.i:. !'://'). which 

 with tlif crexvnt of tin* Ilinl. -li>i!^ateN into t he primit i\e Bin 

 tin- latt. r occupie> the po-terior half <>f tin- embr\ :i (fig. 89 



.1 ///). and exhil.it> a distinrt groove, that i- llankud lv a ri-ht ai:<l a 

 !i-ft ridur like told. ^LVanpaiv with thi> the Chick a>-hown in tig. 85.) 



Fig. 89 A. Embryonic fundament of an 8-days Rabbit, after K;'.I.I.IKKH. 



;/. Fiui(i;uiu-iit of tin- rinluNo ; j>r, priiiiit i\ 



fig. 89 B. Vaacolar area (o> and embryonic fundament (</) of a 7-days Rabbit's tgg, aftr 



:KKU. 



trea (area o\> . Lnmiic fundament ; ;./, pi imitive groove ; r/, meUullary 



f urr. .u . 



Afterwards there appears in this instance, just as with the (hick, a 

 narrow opaque streak in the forward prolongation of the primitive 

 streak, its head process, and thi> divide> the anterior j>ortion of 

 the LT'-rm into a riirht and a left half (ti-:. DO &/*). After some time 

 there are d:-,el..ned on both side> of the head- pnnv tlie medullary 

 f(ld> (!i.u r . >'' 1>). which hound the broad medullary furrow (r/*), ami 

 which, by formings b<>\\ at their anterior ends, become continnou> 

 with each other; but posteriorly they diverge M.mewhat from each 

 other, and embrace the primit ive u'roo\ ( /,/). This >tage correspond* 

 to the condition of the C'hic .-d in lig. 86. 



