148 GEO. S. HUNTINGTON 
Narath that in these forms the right eparterial anlage arises 
from the cranial slope of the first ventral hyparterial bud and is 
hence to be regarded ontogenetically as a branch of the same. 
Even Narath finds himself in difficulties in attempting to sub- 
stantiate his claim on material of his own selection. His best 
illustrations fail to convinee, because the condition they attempt 
to portray, viz., the definition of the bronchial anlagen against 
each other and the future stembronchus, does not as yet obtain. 
In the following developmental stages the anlagen are said to 
‘move apart.’ As a matter of fact the stembronchus declares 
itself and then the individual bronchial buds appear as separate 
derivatives from the same. This ‘moving apart,’ or, to speak 
more correctly, this clearer definition of their relations, cannot 
in my judgment be utilized as evidence that the right eparterial 
bud has ‘migrated’ from the first ventral hyparterial anlage to 
a new and separate point of origin on the stembronchus. It is 
on the contrary a demonstration of two separate and individual 
focal points of entodermal budding which become appreciable 
only when the epithelial model of the future bronchial system 
has become sufficiently defined to make the accurate location of 
-the components in their relations to each other and to the ~ 
stembronchus visually possible. Nor do I believe that we are 
justified, on the evidence furnished by the early epithelial an- 
lagen of this type of lung, in deciding that two adjacent and ap- 
parently in part confluent buds, which later, with the clear defi- 
nition of the stembronchus, appear as two separate branches of 
the same, have rehearsed a greatly foreshortened chapter in 
their phylogeny, in which one of them has ‘migrated’ or ‘shifted’ 
bodily to a new site. All that the very earliest stages show in 
embryos of this mammalian type is a common extremely plastic 
entodermal tube in the process of peripheral budding. This bud- 
ding follows a genetic type which is still seen in the embryos of 
some extant reptiles (lacertilia, chelonia). The individual cir- 
cumferentially disposed evaginations tend to arrange themselves 
into metameric series. 
Hesser (22, p. 236), after describing the pouch-like evagination 
of the cranial pole of the primitive lung-sac in the 8.5 mm. 
