95 



appearance; but. (in a closer examination I have found tin-in in reality to differ 

 not a little in different genera. In the genus Cnnm (I'l. LXVI, fig. 1") there 

 is apparently only a single such sac on each side; but this divides ;it the. end 

 into '2 unequal ranii. and has a slight protuberance above at the base, which 

 may answer to the upper liver-sac in /)i<i*li/lix. In the genus Law/props (tig. 11) 

 there are I liver-sacs on each side, the uppermost of which, however, is much 

 shorter than the other .'!, which have much the same appearance, ;is in I )i<txli/its. 

 In the genus Lrtn-oii (PI. LXVII, figs. 1. 7, <S) likewise, 4 liver-sacs occur on 

 each side, but of very difterent size, the lowest but one being much the Ion- 



t/ 



gest. In LCHCOU fttlr/i* (fig. 8) the 3 other sacs are very much shortened, but 

 less so in Leucon Xttxica (fig. 7). In the genus Pseudocuma (PI. LXVI, fig. 12) 

 I have only found 2 liver-sacs on each side, of nearly equal si/e. and rather 

 regularly annulated throughout, the secretory cells being arranged in successive 

 circlets, and in the genus Cu-wpylnvpis (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-cavity 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 lacunse between the organs. It may, however, be noted 



