678 



ZOOLOGY 



SECT. 



odont 



rad. 



FIG. 577. Triton nodiferus. Interior of the 

 buccal mass, from above, magnified. I. jaic, left 

 jaw ; odoiit. lateral surface of odoutophore ; rad. 

 radula ; r. jaic. right ju\v. 



From the buccal cavity runs backwards a long narrow tube 

 with sacculated walls the oesophagus (Figs. 576 and 578, ccs.). 



Posteriorly this opens into 

 a large ovoid sac the crop 

 (Fig. 576,c/vy). The outer 

 surface of the crop ap- 

 pears marked with numer- 

 ous close-set fine lines, 

 transverse or oblique in 

 direction, and, when the 

 cavity of the organ is 

 opened, it is found that 

 these correspond to numer- 

 ous delicate folds which 

 extend to near the middle, 

 and almost completely 

 block up the lumen. On 

 either side of the crop is 

 a 1 arge gland the S( < / la < i // 

 gland (Fig. 576, /. sal. gl., 

 Fig. 580, r. sal. a!.) partly 

 composed of a compact glandular substance, partly of spongy 

 tissue in which the secretion collects. The two salivary glands 

 are unlike in size and shape, that on the left-hand side being 

 much longer than that on the right. Each has a narrow duct 

 (sal. du.) which runs forwards and inwards to the dorsal aspect of 

 the oesophagus, 

 where the two 

 come into close 

 apposition, be- 

 coming embed- 

 ded in the Avail 

 of the oesopha- 

 gus, along which 

 they run for- 

 wards to open 

 into the buccal 

 cavity. 



From the crop 

 leads backwards 

 and to the left 

 a iiarro\v cylin- 

 drical tube the 

 posterior ceso- 



j>/tagus. On this folloAvs a stomach (Fig. 5*74<,stom.) which is in the 

 form of a U-shaped tube partly embedded in the substance of 

 the liver, the hepatic ducts from which open into it. The tubular 



ja.iv 



. sac 



P IO _ ,j7s Triton nodiferus. Diagrammatic longitudinal ver- 

 tical section of buccal cavity; liod. cur. body cavity; i-ai-t.ca.r- 

 tiln^ of odontophore ; ;'a<r, right jaw; <>*. oesophagus; ,-ml. 

 radula; AC'. .-. radula sac. 



