3S Charles GELDBRD 



it will be noticed that the anterior borders of the plates S, in Anchialiis, 

 are inserted at some distance-in front of the opening of the œsophagus, so 

 that food entering the stomach from the œsophagus must pass immediately 

 between the plates, whilst in our type the anterior borders of the plates do 

 not pass beyond the opening of the œsophagus, cf. fig. 3, 33. 



The surfaces of the plates are covered with stiff hairs ; the lower bor- 

 ders carry a row of spines longer than the corresponding ones in our type 

 which brush against the summit of the ridge c, fig. 34, b. i. 



The grooves between the lower surfaces of the plates and the ridge are 

 much smaller in Anchialus. 



The connection between the plates and the folds S^s, SJ is of the dis- 

 position as in Macropsis. 



The arms bi\ are absent, there is, consequently, no insertion in the 

 hinder part of the terminal end of c; the folds pass without any bend 

 directly from the plates 5, above the ridge, fig. 33. 



The unpaired médian pièce Sj is of the same structure as that of our 

 type, terminating- in a spur-like formation; it possesses, however, three 

 pairs of latéral grooves, fig. 33. 



It is less massive than the corresponding pièce in the Mysidae. 



The dorsal diverticulum is unpaired, and possesses a wide lumen; 

 its summit is directed forwards, fig. 33. 



The cardiac and pyloric cavities do not possess any spécial détails 

 which are wanting in the Mysidae, except the existence of the fold in the 

 anterior région of the cardiac cavity. 



An interesting différence is seen in the digestive glands of Anchialus, 

 which is found also in Siriella; the first pair of dorsal tubes run for- 

 ward a considérable distance above the pyloric and cardiac chambers, 

 FIG. 34, gl. 



They terminate at the same level as the œsophagus above the vault of 

 the cardiac chamber. 



The third dorsal, the latéral and the ventral tubes possess each several 

 of the glandular ridges. 



Siriella. 



The œsophagus is long, running forward obliquely as in our type, 



FIG. 35. 



