Rk. H. Whitehead BaD, 
gland—indeed, there seems to be no reason why it should be regarded 
as anything distinct from that anlage. Probably it is all incorporated 
into the genital gland in the process of development. Thus, in the pig 
of 13 mm. the genital anlage can be traced quite distinctly through at 
least 35 sections (10 mik. each) anterior to the caudal extremity of the 
adrenal anlage. 
There is no evidence of atrophy in the Wolffian body, signs of which 
do not appear until a much later stage. This observation is in accord 
with the statement of MacCallum,” that evidences of degeneration in 
the pig’s Wolffian body do not occur until the embryo is about 100 mm. 
long. | 
In embryos 12 and 11 mm. long the appearances are quite similar to 
those just described except as to size. 
In the pig of 10 mm. the adrenal anlage is still distinctly visible, and 
the thickening on the ventral surface of the Wolffian body (at this stage 
the surface might better be called ventro-medial) is well developed. 
Ventral to the anlage, in the angle between the Wolffian body and the 
mesenteric attachment there is a deep furrow lined by the coelomic epithe- 
hum, which in some situations produces an appearance suggestive of 
Aichel’s finding in the rabbit of an invagination of the epithelium lead- 
ing to the anlage. In most sections, however, the two structures are sep- 
arated clearly by veinlets which emerge from the Wolffian body and run 
ventral to the adrenal. 
In the pig of 8 mm. (Fig. 
3) .the anlage occupies the 
space between the aorta and 
the mesenteric attachment 
medially, the Wolffian body 
laterally, the mesonephric 
arteries dorsally, and the 
coelomic epithelium  ven- 
trally. It does not now ex- 
tend as an unbroken column 
of cells as in > previous é 
are b the previo Fie. 3. Pig 8mm. Leitz obj. 3, oc. 4. -Ad., adre- 
embryos. but is interrupted nal; Mes., mesentery; W. b., Wolffian body; W. d., 
. Wolftian duct. 
at about its middle third. 
This interruption seems to be mechanical, being due to a large glomer- 
ulus of the Wolffian body, which reaches so far medialward as to leave 
no space for the adrenal at this point. The propinquity of the anlage 
!J. B. MacCallum: Notes on the Wolffian body of Higher Mammals. Am. J. 
Anat., Balt., Vol. I, pp. 245-260. 
