32 



and t he outermost has a broad 1>;is;iI attaching portion (PL 



I\, tig. 25, Ce., 1. 'J and •">). The radula. when removed 



from its sac, is aboul 50 nun. Long. In front of the 



tongue is another outgrowth, the Sub-Radular organ, on 



the tip of which opens the duct from the posterior salivary 



glands. Thus the secretion from these glands is poured 



on to the food before it is acted on by the radula (fig. 24. 



s.r.o., vv'i)- This duet enters the buccal mass below the 



radular sac, after running above the sub-lingual gland 



which is ou the ventral surface of the bulb (fig. 24, s.l.g.). 



I he paired ducts from the anterior salivary glands open 



into the pharynx laterally and posteriorly (fig. 24, s.g.d.). 



Thus it will be seen that the massive muscular wall of 



the buccal bulb is formed chiefly by the muscles working 



\\yv jaws and the radula. Anteriorly it is attached to the 



bases of the arms by a circular muscle band (PI. Ill, 



fig. 14, and PI. IV , tig. 20, circ. m.), and posteriorly by two 



ligaments (PL VII, tig. 53). Posteriorly the pharynx is 



continued into the oesophagus. 



The Oesophagus is a narrow tube running clown 

 posteriorly to the stomach (fig. 17, oes.), dorsal to the 

 hepatic gland (PI. V, fig. 38a). Its posterior end marks 

 the limit of the stomodaeum, the stomach, spiral caecum 

 and intestine being hypoblastic in origin in all Cephalo- 

 pods, while that part of the rectum posterior to the 

 aperture of the ink duct represents the very small 

 proctodaeum (Korschelt and Heider). 



The internal surface of the oesophageal wall is thrown 

 into numerous longitudinal ridges (PL IV, fig. 18, and 

 PL V, tig. 33). Internally it is coated by a thin 

 chitinous layer. ridged correspondingly, which is 

 continued posteriorly as the chitinous lining of the 

 stomach (fig. ; ! ; !, Cut. L.). About half-way down, the 

 oesophagus bears a large pouch-like non-glaudular 



