104 
THE VOYAGE OF H.M.S. CHALLENGER. 
ventricle very strong. The blood glands are flattened and of a whitish-yellow colour, 
separated from each other by the central nervous system. The anterior is somewhat 
transversely- oval and bent in the transverse axis; its greatest diameter is 4'5 mm., its 
thickness 1'3 mm. The posterior gland is rather long, 7 ' 5 mm., broader in front, about 
6 mm. and 1 mm. thick.— The two strong retractores branchiae are about 1 cm. long, and 
are made up of a number of separate but interlaced fascicles ; their course is oblique. 
The renal syrinx is short and melon-shaped, of a greater breadth than length, the 
greatest diameter being 2‘5 mm ; it is yellowish in colour; the interior has very strong 
longitudinal folds, which, by their yellow colour, contrast markedly with the brown- 
coloured arborescent villi of the duct ; these latter (fig. 5) increase in size towards the 
lower part. The short and strong duct, of a greyish-brown tint, is conspicuously visible 
through the wall of the urinary chamber, which is 2'5-2 mm. broad anteriorly and about 
3 mm. posteriorly. The anterior end of the chamber bifurcates at about the middle of 
the liver, and the right branch lies in the intestinal furrow ; along the floor of the 
chamber runs on the right side about as far as this bifurcation, the thick duct of the renal 
syrinx (fig. 4, b), which at this jDlace opens by a wide oblique cleft (fig. 4, a), conspicuous 
by its brown papillose tufts (fig. 4). The structure of the kidney was quite as usual. 
The hermaphrodite gland covers the liver with a nearly continuous layer of a some- 
what brighter colour ; in the lobules of the gland are large oogenous cells and spermatozoa. 
The anterior genital mass is large and compressed, and somewhat heart-shaped, with an 
outer arched and inner more convex surface, and an obliquely flattened anterior surface ; 
the upper and hinder margins sharper but rounded ; the lower margin more flattened ; the 
length of the entire mass about 14 mm. by 11 ’5 mm. in height, and 17 mm. in breadth. 
On the anterior surface are the vesiculse seminales and genital ducts ; the larger part of the 
inner side forms the dirty yellow albuminiparous gland, on the under side of which lies 
the ampulla of the hermaphrodite duct, winding farther forwards and outwards along 
the broad lower surface. The slender whitish duct of the hermaphrodite gland (fig. 12, a) 
winds above the exit of the main bile duct, traversing obliquely to the anterior genital 
mass, and forming a whitish coiled ampulla (fig. 12, be), which, when unrolled, measured 
about 1‘5 cm. with a diameter of some 1‘5 mm. Theshort slender male duct (fig. 12, e ) 
opens into the plano-convex heart-shaped prostate (fig. 12,/). This latter is about 3 mm. 
long, and has a narrow cavity. The first 8 mm. of the vas deferens (fig. 12, g) are thin, 
but it increases in thickness farther on and becomes muscular (fig. 12, li ) ; the vas deferens 
then passes into the thicker pern’s (fig. 12, ii), cylindrical in form, and about 15 mm. long. 
For the whole of its length, the penis, and especially its preeputium, is lined with a thick 
found in Ceratosorna trilobatum. The female was 12 mm. long, of which 2-5 belonged to the tail, with six pairs ofsac-like 
appendages of the abdomen. The form was very similar to that of Briarella microcephala. There were no egg-bags ; 
on the wall of the pericardium, however, there were scattered a number of round or oval yellowish eggs ‘1 mm. in 
diameter. I discovered also in the cavity of the pericardium three males, about 2-2'5 mm. long, like those I previously 
found in Chromodoris elisabethina {loc. cit., Heft xi., 1877, p. 472, Taf. li. fig. 16a). 
