POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 301 



FIG. 



2-4 Figures showing the position of the pulmonary cavity, in 

 relation to the volutions of the animal. 



PLATE 12 

 * Nervous system 



a supra-esophageal or cerebral ganglia; h infra-esophageal 

 ganglia ; c commissures connecting the supra and infra-esophageal 

 ganglia; d nerves to the ocular or superior tentacles; e ganglionic 

 enlargement at the extremity of the ocular tentacles; f optic nerve; 

 g eye; h nerves to olfactorj', or inferior, tentacles; i ganglionic 

 enlargement at the extremity of the inferior tentacle ; k nerve to 

 mouth ;7^ m nerves supplying the mouth and adjacent parts; n buc- 

 cal ganglia; o commissural cords connecting the supra-esophageal 

 and buccal ganglia; p nerves supplying the generative system and 

 the visceral mass; r nerves to the muscular collar and pulmonary 

 cavity; s nerves supplying the basal parts of the animal; t nerves 

 supplying the laterobasal parts of the foot; u nerves to the integ- 

 ument on each side. 



PLATE 13 



The same lettering refers to the same muscles in each figure. 

 Fig. 

 1-2 The retractor muscles of the buccal body, foot and tentacles 



enlarged. 1 retractor muscles of the buccal body; 2 re- 

 tractor muscles of the foot; 3 retractor muscles of the 

 ocular tentacles; 4 muscles continuing to the lips and ten- 

 tacles; 5 muscles of olfactory tentacles; 6 muscles of 

 mouth; 7, 8, 9 muscles of the buccal body; 7 levator 

 muscle; 8 protractor muscle; 9 depressor muscles. Figure 

 1 shows the muscles as seen from above; figure 2 is a 

 lateral view. 



3 An enlarged section of the tentacles: 1 integument; 2, 2^ 

 tentacular muscles; S, 3^ tentacular nerves; Jf, Y ten- 

 tacular ganglia; 5 optic nerve; 6 eye; 7 muscles to the 

 mouth; 8 nerves to mouth. 



