132 Proceedings of the Royal Physical Society. 
Alimentary Canal of H. ater, adult. (Figs. 13 and 14.) 
The alimentary canal of H. ater may be divided into three regions—the 
foregut, the midgut, and the hindgut. The foregut comprises the cesophagus or 
cullet, the crop and the gizzard or proventriculus. The midgut comprises the 
ventriculus and the stomach with its diverticula. The hindgut comprises 
the intestine with its malpighian tubules, the colon and the rectum. The 
foregut terminates at the junction of the gizzard with the ventriculus, the — 
midgut at the malpighian tubules, and the hondgut with the rectum or anus. ~ 
Fic. 13.—-Alimentary Canal of H. ater, Pk. 
Oe, C&sophagus. Vi). Sails, 
Or. Crop: Mp. Malpighian tubules. 
G, Gizzard, Ff. Rectum. 
Foregut.—The foregut opens at its junction with the hypopharynx and 
the epipharynx, which form the entry to the cesophagus. The cesophagus 
is a narrow tube which dilates gradually to form the crop. No glands open 
into the cesophagus. The crop narrows slightly at its junction with 
the gizzard, which is easily recognised by its brown, strongly chitinous 
appearance. In cross-section the gizzard is roughly octagonal in shape. It is 
composed of eight plates (Fig. 14), each bearing a complex arrangement of teeth 
and bristles which, doubtless, serve for the crushing and tearing of the bast and 
