ORGANS FOR SPERM-TRANSFER 249 
On the dorsal face, fig. 11, the external mass is confluent with the 
median mass, without boundary line. Thus the distinction be- 
tween the two masses is useful chiefly on the anterior face where 
they form the two sides of the groove. 
In fig. m1, the long triangular region running from the notch 
that marks off the neck from the spiral region and ending distally 
in the rounded and pointed canula, is to be regarded as made up 
chiefly of the median mass, but the depressed part along the left 
edge is part of the external mass. 
On the median face, fig. 11, (which is unfortunately turned so 
that part of the posterior face shows) the external mass shows 
only its preximal end along the side of the diagonal groove, and 
into this groove the external mass here sends a narrow horny shelf, 
dimly seen as light in fig. 11. The external mass has an angular 
projection, or lip, at the very beginning of the groove which will 
be deseribed in connection with the orifice of the groove. At the 
tip, part of the external mass is seen making the lower part of the 
canula, to the right, that is, the curved strip of external mass seen 
is flat and on a lower level than the median mass. 
On the ventral face, fig. 1, the median mass looks like a long 
rounded white bone that begins suddenly without apparent con- 
nection with the neck and, after running nearly straight for some 
6 mm., turns externally across the external mass as a flat, curved 
process that we will call the spatula. Beyond the spatula, which 
stands out freely as the second tip of the appendage, the median 
mass continues as the narrow median edge of the canula. From 
the external view, fig. Iv, the visible part of the median mass, the 
spatula is back of the external mass. 
In the dorsal view, fig. 111, the main part of the spiral region is 
median mass, forming a long triangle, beginning at a deep notch 
near the neck and extending in the foreground as the vis ble part 
of the canula and back of that as the spatula. At the notch may 
be seen part of the lip on the external mass. 
The median face best shows the median mass, but, fig. 11, beg 
not an exactly median view, does not do justice to it. In reality 
this face is markedly flat where it comes against the like face of 
of the other stylet of the pair. This flat face is a long ellipse, 2 
