( 665 ) 
mentioned lobe divides into a right and a left half, and as soon as 
this division has taken place (figure 3d) a lumen appears in both 
halves. These two halves might be designated as the horns or cornua 
of the Lobulus bifureatus. In section they are hook shaped, the outside 
plane is, especially in the foremost part, very concave. Both horns 
become more pointed towards the hind-parts, preserve however their 
lumen nearly to their extremities. These ends lie on either side of the 
infundibularstem (figure 39). Into the hindmost part of the Hy pophysis 
vesicle the nervous part is invaginated. This pars nervosa is not 
completely surrounded by the pharyngeal one, the part that is turned 
to the back remains free. 
If we contemplate the shape of this vesicle more carefully, we 
can clearly distinguish a central part and two lateral paris. Especially 
in the foremost half, where the comb-shaped protuberance of the 
central part begins, these lateral parts are very distinct. As appears 
likewise from Figure 2, they can be followed as far as the hindmost 
part of the vesicle. From what I know about the first origin 
of the Hypophysis vesicle of other Primates 1 do not feel the least 
doubt that these lateral parts are the lobuli laterales, described by 
Gaupp with the Reptiles. I repeat that it is in these lateral lohes 
that, with Primates, the ensuing histological differentiation of the 
Hypophysis vesicle is continued. They form consequently an essential 
ingredient part of the Hypophysis. 
I shall not venture to express a view of the signification of the 
lobulus bifureatus. Certain it is that the two cornua do not play 
an important part in the further development. This appears from 
the condition found in an older Embryo (Embryol. Laborat. Utrecht 
Tarsius N°. 555). Three sections through the Hypophysis of this 
specimen are represented in Figure 4. Section « in this figure is 
nearly similar to Figure 35. One recognises the foremost part of the 
vesicle, differentiated to cell-stems, but the part of the Lobulus 
bifureatus (ridge-shaped in the section) lying above it shows also a 
similar course of development. On the top of it lies the section 
of the beginning of the cornua, each provided with a lumen. The 
fact that the latter likewise still show progressive symptoms of 
development, appears from Figure 45, where on either side of the 
infundibular-stem groups of cells are found, among which there are 
some with a lumen, which have taken their origin in the cornua, 
And that such epithelium-isles extend as far as the hindmost edge 
of the infundibular-stem appears from Figure 4c in which a section 
is sketched, lying behind the above-mentioned stem, and where 
after all, at least on one side, remains of the Lobulus bifurcatus are found 
