L. E. Robinson and J. Davidson 
417 
while the posterior lobes of the organ lie in contact with the anterior 
surface of the rectal sac, and may even extend backwards for some 
distance in the lateral regions of the body on either side of the 
latter. 
An examination of sections of the gland shows it to be composed 
of two distinct types of tissue, the one of a spongy nature and the 
other granular. Each type is confined to certain lobes of the gland, 
and in no case do the two types appear together in any one lobe. 
The lobes which are composed of spongy tissue are attached by 
their bases to the lateral and ventral walls of the constricted proximal 
portion of the ductus ejaculatorius ; they are four in number and from 
their respective positions may be termed the anterior and the posterior 
spongy lobes. The anterior lobes, as mentioned above, extend forwards 
on either side of the external genital opening almost to the basis 
capituli; the posterior lobes run backwards along the middle of the 
lateral surface of the body of the gland, and almost reach the posterior 
limits of the organ. Fig. 3 (Plate XXVII) represents a transverse section 
passing through the anterior opening of the seminal vesicle, the con¬ 
stricted pi’oximal portion of the ductus ejaculatorius and the four spongy 
lobes. The upper pair of the latter are the anterior lobes and the lower 
and larger pair the posterior lobes. In structure, the spongy lobes are 
seen to consist of a connective tissue stroma, the lacunae of which are 
distended with a clear pale secretion. The external surface is closely 
invested by a delicate connective tissue sheath, near which most of the 
nuclei lie. The latter are of moderate size and ovoid in shape; they 
are very rich in chromatin, which is distributed in irregular clumps 
immediately beneath the nuclear membrane. Isolated nuclei, which 
show appearances of dissolution, are scattered in limited numbers in the 
more central portions of the lobe. The lacunar spaces of the stroma 
unite to form a short duct ( d.a.s.l ., d.p.s.l.) within the substance of 
the gland, which opens directly into the constricted portion of the 
ductus ejaculatorius ; through its lateral walls in the case of the anterior 
lobes, and by a pair of adjacent openings in its floor in the case of the 
posterior lobes. 
The remaining lobes, which form the greater part of the accessory 
gland, are collectively of the granular type, and, unlike the spongy 
lobes, they all derive their origin as offshoots of a small median 
unpaired lobe which lies in the anterior portion of the ventral part 
of the body of the gland. Fig. 4 (Plate XXVII) represents a transverse 
section which passes through this median granular lobe of the white 
