ETJPAGTJRTJS. 511 



appreciable chemical action being exerted by the 

 oesophageal and labial glands on the lumps of food 

 soaked in sea-water which pass up the tube. 



The oesophagus terminates on the underside of 

 the Stomach (figs. 21 and 19). Its opening is guarded 

 by a pair of calcified flaps densely fringed with setae. 

 The cardiac portion of the stomach (cardiac fore-gut of 

 Pearson) is considerably larger than the pyloric portion. 

 It is a large membranous bag with a flat roof. The 

 ossicles present in this and the hinder part of the stomach 

 do not diverge sufficiently from the typical form in the 

 Decapod Crustacea to justify a detailed description.* 

 The cardiac ossicle is far more slender than is usual, and 

 is bow-shaped ; the pterocardiac ossicles are also slender, 

 and articulate with the long curved zygocardiac bars. 

 The pterocardiac ossicle is almost vertical. Viewed from 

 the side, the oesophageal plates are seen to join the post- 

 pectineal ossicle. Infero-lateral cardiac teeth are present. 

 When the stomach is cut open in sagitto-longitudinal 

 section the general structure of the apparatus can best 

 be seen (fig. 19). The lateral teeth are unusually 

 massive and are prolonged backwards into strongly 

 pectinated ridges. The summit of the cardiopyloric 

 valve also bears a ridge of great blunt setae like a comb. 

 A pectineal tooth is present. There are five valves 

 opening into the intestine, a superior median valve 

 excavated ventrally (fairly large in this species), a pair 

 of dorso-lateral valves and a pair of smaller infero-lateral 

 valves, both richly setose. On the roof of the pyloric 

 region is a pair of semi-circular ridges of setae, and 

 between them a median ridge bears a bunch of setae. 



* See Huxley's ' Crayfish,' Pearson's ' Cancer,' Bronn's ' Thierreich,' 

 Bd. V. 2, and many practical text-books. 



