486 



The Embryology of Hylodes Martinicensis 



completely separated from the gut, the oesophagus is flattened dorso-ven- 

 trally, and loses its lumen (Fig. L) . The solid portion of the oesophagus 

 extends for a little distance anterior and posterior to its union with the 

 lungs (Figs. LI, 2 and HI, oe, rlu). The lung rudiment lengthens and 

 becomes paired posteriorly. 



The foregoing description shows that by the time stage VIII is reached, 

 the principal adult organs derived from the archenteron are well differ- 



ta 



Fig. L. Cross sections of stage VIIT. 1 anterior to 3 (both anterior to Fig. HI), acv, an- 

 terior cardinal vein ; ao, aorta ; au, auricle ; Cv, Cuverian vein ; hk, head-kidney ; oe, 

 oesophagus; rlu, rudiment of lung; scv, subclavian vein; ta, truncus arteriosus; v, ven- 

 tricle; y, yolk-mass. 



entiated. The liver, after stage VIII, becomes more compact; it is less 

 intimately connected with the heart, and definite efferent hepatic vessels 

 are formed. The gall-bladder increases in size and after stage X contains 

 a clear, yellowish substance. The three rudiments of the pancreas be- 

 come unified into a compact organ. The lungs increase in size, and soon 

 after stage VIII hang freely in the body cavity, surrounded by the 

 splanchnopleure. Their walls and the walls of the oesophagus are some- 

 what pigmented after stage XII. The lungs, even as late as the time of 



