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. They are arranged in 2 sets, and. as above mentioned, are ap- 

 pended to the end of the ventral expansion of the stomach. Kr0yer has 

 already observed these sacs in Diastylls: 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 PI. LXV, figs, i, 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, sharply contrasting with 

 the dark-coloured stomach. In its natural position, the upper sac on each side 

 (I 1 ) curves upwards at the end, beyond the dorsal face of the stomach, whereas 

 the other 2 (I 2 , P) 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 



