The anatomy of Lottia gigantea Gray. 63 



Sup. I supra-intestinal ganglion Vg visceral ganglion 



t tentacle Vn, Vn\ Vn" visceral nerves 



tn, in' tentacle nerves Vis. A visceral artery 



ul, ul' nerves to lips X vein from buccal sinus to mantle 



V ventricle x, y, 8 nerves from right pleural 



Val auriculo-ventricular valve ganglion to intestine and visceral 



V.Br ventral branch of visceral artery 



artery 1 to 25 muscles of buccal mass, 



Vf ventral or lesser fold of pharynx described in text. 



and oesophagus 



All figures are of Lottia gigantea. 



Plate 1. 



Fig. 1. General view of the alimentary canal and gonad. The 

 dorsal wall of the body, pericardium, heart, and all the liver etc., have 

 been removed. The buccal sinus is opened to show pharynx and 

 pharyngeal glands. 2:1. 



Fig. 2. Oral cavity, pharynx and portion of oesophagus seen from 

 above. The dorsal wall has been slit open longitudinally just to the 

 right of the median line, so that the greater part of the dorsal wall is 

 turned to the left. 6:1. 



Fig. 3. Dissection of head, viewed from the right side, to show 

 relation of buccal mass, pharynx, arteries and nerves to each other. 

 The space between the buccal mass and pharynx is greater than is 

 usual in life. Cerebro-pleural and -pedal connectives are shown in side 

 chamber. 8:1. 



Fig. 4. Side view of buccal mass and oral cavity to show relations 

 of radula, subradular ganglia, and also certain muscles which operate 

 the radula. 4:1. 



Fig. 5. Ventral view of buccal mass to demonstrate muscles de- 

 scribed in text. 4:1. 



Fig. 6. Oesophagus isolated to show spiral course of the folds on 

 its inner wall, and the two pairs of salivary glands. 2:1. 



Fig. 7. Section showing three zones on lips, especially the area 

 of small teeth (At). 100 : 1 (from small specimen). 



Fig. 8. A bunch of acini or glandules of the pharyngeal or 

 posterior salivary gland, much enlarged. 



Fig. 9. Side view of buccal mass to show arrangement of muscles 

 described in text. 4 : 1. 



Fig. 10. The buccal mass seen from above, the pharynx having 

 been removed, and the right half of jaw (J) also. Drawn to show the 

 muscles. 4:1. 



Fig. 11. Drawn to show the radula (_R), palps and sublingual or 

 subradular organ (seen between them) in position when animal is feeding. 

 3-4 : 1. 



