-268 



s. GOTO ; 



The secondary left posterior eaterocoel encircles now the marginal 

 •portions of the stomach, forming a, ring; but this ring is incomplete in 

 the maclreporic interradins, wliere tlie two arms reniiiin permanently 

 separated b}^ the dorsal mesentery containing the axial sinns. Com- 

 pare Fio-s, 28&o7-ol). Conformini;- with the ü'ut in its î^eneral outline 

 as seen in the antero-p(Xsteri(.)r direction, it sends out diverticula into the 

 iirms, in which it occupies not only the oral side of the gut but ex- 

 tends also on the aboral side, so that the mesentery separating it from 

 the epigastric enterocœl lies always on the abi^ral side of the gut. The 

 diverticula into the arms are in stnges G and H still simple, but 

 subseijuently undergo a change of form corresponding to the change in 

 form of the e[)igastric enterocœl, to the description of whicli we shall 

 now pass on. 



The central portion of the epigastric enterocfcl presents nothing 

 worth noting ; we shall therefore concern ourselves only with its 

 diverticula. These are, as already noted, at first simple, but hand in. 

 hand with the change of form which the hepatic cœca undergo, these 

 diverticula also pass through similar changes. When the rudiment 

 of each hepatic cœcum begins to divide into two branches to form the 

 definitive double cœcum the diverticulinn from the epigastric enterocœd 

 also begins to ])e prolonged into two brandies, lioth liranches lying 

 on the aboral side of the hepatic cœcum, and terminating at a short 

 distance from the tip of the latter. Tiie successive changes of form 

 wliich the epigastric enterocœl undergoes can therefore be represented 

 by cut o. It need hardly be added that the diverticula of the second- 

 ary lefc posterior enterocœl undergo a corresponding change to the 

 above. 



The perùïîsophageal enterocœl has changed considerably com- 

 pared witli what it was in stage F. It has grown completely around 

 the stomach, and its two ends have grown together and fused with 



