94 
at the same time contracting to the narrow cylindrical intestinal tube, which 
traverses the remaining part of the body. On a closer examination (see PI. LXV, 
figs. 2, 3, 4), this dilated part, or stomach, as it may be termed, is found to 
consist of 2 divisions, differing in the structure of their walls. The anterior 
division exhibits a rather strong chitinous coating, which inside projects in 
several setiferous lappets and thickened fillets clothed with stiff hairs, which in 
some places are arranged in a fairly regular comb-like manner. It answers to 
the so-called triturating stomach in higher Crustacea, and forms below a rounded 
expansion, to the end of which the liver-sacs are appended. Along the ventral 
face of this expansion, the setiferous fillets are arranged in a peculiar manner 
(see figs. 3 & 4), serving apparently as a filter, to prevent the alimentary matter 
contained in the stomach from entering the liver-sacs. The walls of the posterior 
division of the stomach (see figs. 2 & 3) are quite soft, and exhibit numerous closely- 
set circular muscle-fibres, which behind gradually assume a more oblique course. 
They are, more-over, lined inside with large oblong, secretory cells, arranged 
at some distance from one another in oblique rows. The intestine proper (i) 
forms a narrow tube, which, in the exposed part of the trunk, runs nearer to 
the ventral face, whereas in the posterior division it occupies the axis of the body 
(see PI. LXV—LXVIII, fig. 1). Its walls are rather thin, and, like the posterior 
part of the stomach, exhibit closely-set circular muscles, but are without secretory 
cells. In the last segment it terminates in a short muscular rectum, which opens 
in a longitudinal anal aperture situated on the lower side of this segment, or, if a 
telson is present, on the lower side of this part, more or less distant from its base. 
The liver-sacs, unlike what is the case in Amphipoda and Isopoda, are 
comparatively short, being chiefly confined to the part of the body covered by 
the carapace. I hey are arranged in 2 sets, and, as above mentioned, are ap¬ 
pended to the end of the ventral expansion of the stomach. Ivroyer has 
already observed these sacs in IHastylis: but he erroneously believed them to 
originate from the dorsal face of the stomach. In the above-named genus they are 
3 .in number on each side (see PL LXV, figs. 1, 2, 10 1, PI. LXVI, figs. 1, 9), 
issuing from a short common trunk, and are of about equal size, cylindrical in 
form, and each terminating in a short filament. They are irregularly wrinkled, 
owing to the large secretory cells lining their walls (see PI. LXV, figs. 7, 9), 
and in the living animal exhibit a deep yellow colour, shai'ply contrasting with 
the dark-coloured stomach. In its natural position, the upper sac on each side 
(l 1 ) curves upwards at the end. beyond the dorsal face of the stomach, whereas 
the other 2 (P, F) extend straight backwards along the sides of the stomach. 
At first I believed that the liver-sacs in all Cumacea were of the above-described 
