The anatomy of Lottia gigantea Gray. (35 



aorta is shown in red. The muscular portion of the ventricle is shown 

 differentiated from the thin-walled portion next to the aorta. A small 

 section has been cut out of the dorsal' wall of the auricle to show the 

 interior and the connection with mantle spaces and efferent ctenidial 

 vessel. 5:1. 



Fig. 25. A section through a dorsal fold of the oral cavity, 

 showing large mucous cells. Much enlarged. 



Fig. 26. A portion of the pericardium, and right and left nephridia 

 to demonstrate the two reno-pericardial canals. Both right and left 

 nephridia have been opened; the left drawn semi- diagrammatic. A 

 portion of the wall of the forward part of the right nephridium is 

 turned back to give an idea of the actual appearance of the fenestrated 

 dorsal wall. The reno-pericardial canals are shown in red. Much 

 enlarged. 



Fig. 27. Arterial circulation of foot , seen from above ; semi- 

 diagrammatic. The pedal arteries are drawn in red, the anterior pedal 

 arteries in black, and the neural arteries in gray. Posterior portion of 

 buccal sinus in shown in black dashes and the anterior part of the 

 pedal nerve cords is drawn in to give a further idea of relations. 

 11/, :1. 



Plate 3. 



Fig. 28. Left pleural ganglion, much enlarged to show the otocyst. 

 Lig ligament uniting the two otocysts ; Lig' that binding otocyst to 

 pedal ganglion; Lig" that binding the otocyst to the pleural ganglion. 



Fig. 29. Section through eye, much enlarged, to show the heavily 

 pigmented "retina". 



Fig. 30. A general view of the nerves to foot and mantle, with 

 special reference to the pallial nerves, which supply the circumpallial. 

 5 : 1. 



Fig. 31. Detail of nerves leaving left osphradial ganglion to inner- 

 vate the left osphradium, seen from above. Much enlarged. 



Fig. 32. Detail of a portion of mantle to show nerves (M. N') 

 lying in dorsal wall. 



Plate 4. 



Fig. 33. General view of cerebral, pleural, pedal, labial, sub- 

 radular and stomatogastric ganglia with connectives, to show relations 

 one with another. All the nerves given off by the cerebral ganglia are 

 shown in this figure. 5:1. 



Fig. 34. Front view of head and lips, showing nerves and their 

 branches given off to lips from cerebral ganglia. Enlarged like last. 



Fig. 35. A general view of the visceral loop, with supra- and 

 subintestinal ganglia, visceral ganglion, and their nerves, together with 

 the pharynx and a portion of the stomatogastric system. The dorsal 

 body wall and pericardium have been removed. 4:1. 



Zool. Jahrb. XX. Abth. f. Morph. 5 



