ON THE NFDIBRANCH1ATA. 



15 



split in two. This central tooth (fig. 1) is broad, and bears a strong pointed median 

 cusp and eight lateral denticles on each side. The divisions between the denticles 

 are continued as strise on the body of the tooth. The first lateral (fig. 2) tooth is 

 roughly triangular in shape, and bears about twelve fine distinct denticles on the inner 

 side, facing the central tooth. The second lateral (fig. 3) is similar, but the top part 

 is somewhat straighter and more pointed, and the denticles rather fewer (eight to 

 nine). The third lateral (fig. 4) is still narrower and more pointed, but has about 

 the same number (eight to nine) of quite distinct denticles. The fourth lateral (fig. 5) 



Fios. 2, 3. First and second lateral teeth. 



FIG. 1. Three median teeth, from above. FIGS. 4, 5. Third and fourth lateral teeth. 



FIGS. 1 to 5. Notaeolidia r/igas. 



is smaller, and bears about seven indistinct and inconspicuous denticles. The fifth, 

 when it exists, is a minute elongate smooth plate. 



The salivary glands are two long white flocculent bands, 23 m. long and 4'5 wide. 

 The digestive organs are almost empty in the larger specimens, and so crushed and 

 compressed by the various parts of the reproductive system as to suggest that the 

 animals do not take much nourishment during the breeding season. The rather short 

 oesophagus leads straight into the stomach, which lies on the top of the much swollen 

 mucous gland. The interior of the stomach is laminated. From it proceed two tubes, 

 which enter the body wall right and left. Just below them issues the intestine, which 

 goes first to the right and then turns backwards. At its commencement it bears 



(ROT. soc. EDIN. TRANS., VOL. XLI., 523.) 



