112 ^- MITSUKURI; 



weitaus grÖ8ste Theil der untern Urdarmwand aus einen einsichtigen 

 Flattcüepithel bestand." {p. 42). 



(f). When the invagination cavity breaks through below in 

 Plati/dacti/his and Cistuào, the floor of the cavity showed, according to 

 Will, extraordinary net-like appearances ( 93 ; Figs. 66, Ih, and 8&, 

 '92 Fig. 17). In Lacerta, (at least in the specimen which Will 

 had) the invagination-cavity breaks through at only one place. 



{fj). The " KupfFer's Gang ", which I have called the blastoporic 

 passage in the foregoing article, does not become closed at any time in 

 Lacerta, but becomes directly transformed into the neurenteric canal. 



On most of these points, I pointed out categorically in my Con- 

 tribution IV, Postscript, the différences between the results which 

 Will obtained in Flatijdactylus and Cistudo and those which I 

 obtained in Chelonia. It is to he noted that the results n^hich Will noiv 

 gives for Lacerta ajjproach on most of these points nearer mine for 

 Chelonia than those he brovght out for the two species which he studied 

 before. 



After the breaking through of the invagination cavity, the dorsal 

 wall of the cavity is said by Will to spread itself still further in 

 breadth. " Wenn demnach bei der Eidechse, anders als beim Gecko, 

 der Urdarm noch vor Errechnung seiner definitiven Länge und 

 Breite noch unten durchbricht, so wächst doch die dorsale Urdarm- 

 wand selbstständig genau in derselben Weise weiter wie vor dem 

 Durchbruch." (p. 54). The growth is probably the same thing as the 

 spreading of the primitive knob which I described in my Contribution 

 IV. On p. 250 of that paper, I said, summing up the process. 

 " The primitive knob which was gradually spreading itself over the 

 ventral surface of the embryonic shield before the breaking through 

 of the invagination cavity continues to do so after that event. It spreads 

 from the spot where the invagination-cavity first broke through away 



