XXI PROBOSCIS—-ALIMENTARY SYSTEM 515 
In some cases, where the proboscis itself is short, as in 
Pallene, this mechanism is carried backwards into the fore-part 
of the body; and, in, the latter genus, the narrow oesophagus 
"Dil M 
Fic. 278.—Transverse sections through the proboscis of Ph. charybdaeus. A, Anterior, 
through the principal ganglionic mass (G@) ; B, posterior, at the level of the sieve- 
hairs (1). Coec, Intestinal caeca ; Dil. M, dilator muscles ; NV, inner nerve-ganglion, 
with circular commissure ; V’, outer nerve; or, chitinous lining of oral cavity ; 
RM, Ret.M, retractor muscles. (After Dohrn.) 
which succeeds the masticatory apparatus is likewise provided 
with extrinsic muscles. 
The oesophagus is followed by a 
long gastric cavity, which sends forth 
caecal diverticula into the chelo- 
phores (when these are present), 
and four immensely long ones into 
the ambulatory legs. The caeca are 
attached to the walls of the limb 
cavities, especially at their extremities 
in the tarsi, by suspensory threads 
of connective tissue, and the whole 
gut, central and diverticular, is further 
supported by a horizontal septal mem- 
brane, running through body and legs, 
which separates the dorsal blood-vessel 
and sinus from the gut, the nervous 
Fic. 279. — Transverse section 
through the basal joint of the 
third leg in Phoxichilus charyb- 
daeus, 2. Cut, Cuticle; Hyp, 
hypodermis ; Jn, intestinal cae- 
cum; JV, nerve-cord; Ov, ovary ; 
Sept, septum. (After Dohrn.) 
system and the ventral sinus, giving support also to the reproduc- 
tive glands. A short and simple rectum follows the gastric cavity. 
In Phoxichilus, which lacks the three anterior appendages in 
the female and the two anterior in the male, two pairs of caeca run 
‘from the gut into the cavity of the proboscis (Fig. 278, B, coec.).! 
1 Dohrn, ¢. cit. p. 
55. 
