DORIDOEIDES GARDINERI. 285 
The heart (fig. 7) lies somewhat to the right of the median 
line. The walls are thin, and not strong. From the ventricle 
issue the anterior and posterior aortas, but the aortic system 
is not much developed, as is perhaps natural in an animal 
that has no gills. The arteries are thin, and do not extend 
beyond -the level of the genital orifice in front and of the 
anus behind. The musculature of the ventricle also is feebly 
developed. The venous system is extensive and the veins 
are provided with valves (fig. 8) not only near the heart but 
in parts far from it, e.g. throughout the length of the lateral 
veins and venules and between the blood lacune of the foot. 
The auricle (fig. 7, c) has a large extension (fig. 7, d) on the 
left, enclosed by a corresponding extension of the pericardium ; 
it adheres to the anterior part of the ventricle, the line of 
adhesion being zigzagged, and on the right it is attached to 
the wall of the pericardium. 
The kidney (see text-figure) is a shallow chamber lying on 
the surface of the hermaphrodite gland, and sending down- 
ward prolongations between its follicles. In front it bifur- 
cates like the hermaphrodite gland and is divided behind into 
a number of irregular tubes by the dorso-ventral muscles and 
the projecting genital lobes. The renal opening (c) is minute 
and near the anus. From the reno-pericardial opening (a) 
a tube passes dorsally through the substance of the kidney 
and dilates in the median line into a flattened vesicle. Pos- 
teriorly this sub-divides into three fine ducts, each opening 
into the kidney by a minute aperture. The wall of the 
kidney is formed by a layer of large, clear, cubical cells, the 
nucleated protoplasmic portion of which is limited to a 
small quantity at the base of the cell. 
The genitalia (fig. 9) are large, and occupy most of the 
right-hand side. The hermaphrodite gland (fig, 9, a, and 
fig. 10) consists of a single undivided mass of roughly 
triangular shape, bifurcating in front so as to enclose the 
ampulla and the spermatotheca in the fork. It is traversed 
by branches of the liver, which enter it from below, by the 
dorso-ventral muscle bands (fig. 10, d) and by various pro- 
