BLOOD AND VITELLINE VESSELS IN AMPHIBIA 359 
Branches from the left vitelline vein are given off to the liver, 
in this and later stages to form the hepatic veins; that portion of 
the vitelline vein which is back of these vessels might be called the 
subintestinal vein. 
In a specimen 10 mm. long, about the same conditions were 
observed as in the last. There is a similar development of the 
lateral cutaneous vessel (fig. 10). The yolk vessels are small, but 
definite and lined with endothelium, and there is a larger central 
vessel on the ventral side of the yolk. The lateral cutaneous veins 
are similar and with no very extensive branches. The blood cor- 
puscles are now well formed and much like those of the adult; 
both red and white may be distinguished. 
In a specimen 12 mm. long, the intestine is well formed and we 
may recognize the hepatic-portal vein in connection with it. 
The lower portion has been formed from the left vitelline or the 
subintestinal vein. According to Hochstetter (’87), in Salaman- 
dra maculosa the vitelline vein retains its subintestinal relation 
throughout its entire length while inS. atra, Triton and Pleurodeles, 
the subintestinal vein passes around upon the dorsal side of the 
intestine and opens into a trunk of the portal vein. In this speci- 
men of a 12 mm. Amblystoma the left vitelline has become some- 
what changed in its cephalic portion, with the decrease in yolk 
and increase in differentiation of the intestine, while its upper 
portion has been developed into a more dorsal vessel. Hoch- 
stetter (87) and Kellicott (05) in Ceratodus, apparently in some 
forms at least, consider this more cephalic portion of the hepatic- 
portal to be a new formation. From what I have seen of Ambly- 
stoma I believe it is not entirely new, but rather a transformed 
portion of the left yolk vessel. The lateral cutaneous vein is 
large and branches from it extend down close to the epidermis. 
The ventral extent of these is least in the cephalic region. They 
extend about half of the way down in the middle portion of the 
body and two thirds of the way in the caudal region. 
It is not until the larvae are quite large that a ventral abdomi- 
nal is developed (fig. 11), formed, I believe, by the growing down 
of cutaneous vessels. It arises from some of these cutaneous ves- 
