196 Seminal Products in Limpets. By W. H. Dail. 
Second, the superior wall of the right-hand (and only fully 
developed) renal sac. By means of delicate, but tough columnar 
walls of tissue, forming connected cellular cavities, overlaid with 
semi-glandular tissue for the elimination of the renal secretions, the 
upper wall of this sac is connected with, 
_ Third, the floor of the sae, of similar constitution and tough- 
ness. ‘The two are readily separated owing to the greater delicacy 
of the connecting tissues, but the upper wall and the mantle, and the 
lower wall and the tissues below it, are very intimately connected 
by membranous fibres of such toughness as to render their separa- 
tion without injury very difficult. 
A muscular band or mesentery of considerable strength, having, 
in the specimens of Ancistromesus examined, a width equal to 
nearly one-twenty-fifth of its length; extends completely around 
the internal viscera which are compactly bound together by similar 
tissue. 
From the floor of the renal sac similar but short mesenteric 
bands extend downward to the peripheral band, radiating from the 
apex of the shell, and having, when in their natural position, a 
somewhat triangular form; the short sides of the triangles cor- 
responding to the distal ends of the radii, and their plane surfaces 
being nearly vertical to the horizontal plane of the visceral mass. 
In the specimen under consideration there were one posterior and 
ten lateral bands of this nature, five on each side. In details of 
form and dimensions these vary in different individuals. They 
widen at their junction with the tissues above and below, and send 
off numerous fibres in all directions, and especially to the peripheral 
band. We thus have as it were the entire visceral mass suspended 
in the perivisceral cavity, free of the floor and sides of the latter 
(except a delicate anchoring membrane, lying vertically in the 
median line and connecting the median line of the visceral mass 
with that of the muscles of the foot), but in contact or close con- 
nection with its roof which is composed of the floor of the larger 
renal sac. This sac opens externally by a prominent papilla to 
the right of the anal papilla, while the smaller (and usually almost 
abortive) left renal sac, opens by a proportionally smaller papilla to 
the left of the anal. 
The specimens were examined by cutting away the solid mus- 
cular foot, and thus exposing the perivisceral cavity without in 
any way lacerating its contents, sides, or upper surface. A number 
of individuals were dissected without coming any nearer to the 
object in view. At last, however, a specimen was taken up which 
appeared to solve the difficulties and afford the long-sought-for 
explanation. It wasa male. The surface of the viscera with one 
exception was perfectly normal. On the right-hand posterior 
portion of the periphery of the testis, covered with its usual delicate 
