( 660 ) 
which the two tangents in the point 5 are identical with the tangents 
ue Ean, == 0 
of the curve #, in the same point, then this pair will meet 4, in 
two points U, U,; we obtain the joining line of these points out 
of the equation of the considered pair of conics, i.e. out of 
ant, + (mx,’ — naw) = 0; 
so we have by the latter definition 
U,U,=@e,+d=0 
or 
U,U,=4mnz, + ba, = 0, 
and this is the line passing through the vertex B and the common 
point (7) to the double tangent and the cuspidal tangent. Therefore 
the four points U,, U,, B, and M lie on a straight line. 
On each line passing through J/ we have obtained four points 
of k, as intersections of this line with two conics belonging to a 
pencil, which has three consecutive base-points in A, and the fourth 
base-point in 5. To this pencil of conics belongs also the pair of 
lines v, =O, x, =O as a degenerated conic. We can now say, that 
on each line s, passing through J/, the two pairs of intersections 
with #,, the point M and the common point to s and wv, =O are 
three pairs of elements of the same involution. 
All the relations considered here, remain unaltered, if the double 
point B is a “conjugate point” (aenode). 
Anatomy. — “On the development of the Hypophysis of Primates 
especially of Tarsius’. By Prof. L. Bork. 
(Communicated in the Meeting of November 26, 1910). 
When studying an Embryo of Tarsius spectrum belonging to the 
embryological Institute of the Utrecht University (Catalogued as 
Tarsius n° 666), my attention was drawn by the peculiar shape of 
the pharyngeal part of the Hypophysis. In this Primate a form is 
developed more complicated than is known to us in other mammals. 
In most cases we know, as follows from the description of various 
authors, that the Hypophysis-vesicle unstrings itself from the roof-epithe- 
lium of the stomadeum, places itself against the anterior surface of the 
infundibularstem, and is then, when the nervous part of the Hypo- 
physis begins to develop, invaginated by the latter. The pharyngeal 
— or more correctly expressed — the oral part of the Hypophysis 
