95 
appearance; but on a closer examination I have found them in reality to differ 
not a little in different genera. In the genus Cuma (PI. LXVI, fig. 10) there 
is apparently only a single such sac on each side; but this divides at the end 
into 2 unequal rami, and has a slight protuberance above at the base, which 
may answer to the upper liver-sac in Diastylis. In the genus Lamprops (fig. 11) 
there are 4 liver-sacs on each side, the uppermost of which, however, is much 
shorter than the other 3, which have much the same appearance as in Diastylis. 
In the genus Leucon (PI. LXVII, figs. 1, 7, 8) likewise, 4 liver-sacs occur on 
each side, but of very different size, the lowest but one being much the lon¬ 
gest. In Leucon fulvus (fig. 8) the 3 other sacs are very much shortened, but 
less so in Leucon Nasica (fig. 7). In the genus Pseudocuma (PI. LXVI, fig. 12) 
I have only found 2 liver-sacs on each side, of nearly equal size, and rather 
regularly annulated throughout, the secretory cells being arranged in successive 
circlets, and in the genus Campylaspis (fig. 13) these sacs are represented by a 
single large oval pouch on each side lined inside with unusually large, and irregu¬ 
larly disposed, secretory cells. 
2. Vascular System. 
The central part of this system, the heart, is not difficult to observe in 
living specimens, owing to its rapid pulsations. It is situated (see PI. LXV— 
LXVIII, fig. 1, h) dorsally at about the middle of the anterior division of the 
body. Its anterior extremity extends for some distance within the part of the 
body-cavify covered by the carapace, and the posterior extremity reaches more 
or less far into the 3rd exposed segment of the trunk. In shape it is oblong 
fusiform, tapering at each extremity to a narrow neck, which is apparently conti¬ 
nued in an arterial vessel. It exhibits 3 pairs of lateral, fissure-like openings for 
the reception of the blood, of which the middle one, occurring within the 1st 
exposed segment, is especially distinct. The walls of the heart (see PI. LXVII, 
fig. 9) are strengthened by band-like, circular muscles, which, especially in the 
vicinity of the lateral openings, are rather strong. The heart lies imbedded within 
a thin membranous capsule or pericardium, by which it is attached to the dorsal 
walls of the body. 
About the peripheric part of the vascular system, or the blood-vessels, 
I have very little to state. Besides the 2 arterial stems forming the immediate 
continuation of the heart, 2 lateral stems seem to occur in front and one ventral 
behind; but I have failed to trace any ramifications of these stems, which indeed 
seem to open into lacunae between the organs. It may, however, be noted 
