490 



The Embryology of Hylodes Martinicensis 



the vitelline vein conies from the right side of the yolk (where the liver, 

 yolk and gut are connected), passes along the dorsal wall of the liver, 

 and joins the posterior vena cava before it enters the heart. Lastly after 

 about stage VIII, the vitelline vein (Fig. H7-4, vv) is greatly reduced 

 and no longer passes through the liver as a distinct vessel, but is lost in 

 the tissues of the organ. 



The Cuverian veins, the anterior cardinals, and perhaps the posterior 

 cardinals are present in stage IV (cf. Fig. N, with the following de- 



FiG. N. Diagram of veins. 1, stage VIII. 2, stage XV. aa, anterior abdorainal vein ; ac, 

 anterior cardinal vein ; avc, anterior vena cava ; c, cutaneous vein ; Cv, Cuverian vein ; hk, 

 head-kidney; hp, hepatic portal vein; ij, inferior jugular vein; k, kidney; 1, liver; mt, 

 mesonephric tubule ; pc, posterior cardinal vein ; pvc, posterior vena cava ; sc, subclavian 

 vein; sv, sinus venosus; vv, vitelline vein. 



scription). There is also, on each side of the yolk, an enormous cutan- 

 eous vein, which lies in the somatopleure, hence not directly in contact 

 with the yolk-mass, and passes beneath the forelegs into the Cuverian 

 vein. It is so conspicuous from stages VI to IX, that it deserves especial 

 mention as an embryonic vessel (see Fig. LI, 2, scv). From its position 

 the cutaneous vein would seem to be the forerunner of the subclavian 

 vein, but it has not been seen after stage XIL 



The posterior cardinals are evident after stage V. They diverge from 

 a common trunk (2 sections posterior to Fig. H8), and passing an- 



