PACE : ANATOMY OF NATALTNA TKIMENI. 233 



The animal was too contracted for mucli to be made of its external 

 cliaracters. No trace of any "tail-pore" could be discerned. 



The disposition of the internal organs is much affected by the 

 enoraious size of the radula sac : thus, the oesophagus passes to the 

 right side of the radula sac, and the central nervous system, instead of 

 being circum-cesophageal, forms a ring round the buccal mass, the 

 cerebral ganglia being situated entirely on the right side of the latter ; 

 the closely-applied cerebro-pedal and cerebro-pleural commissures are 

 much longer on the left than on the right side. 



A pair of large, closely-approximated ganglia are situated on the 

 radula sac in the angle between it and the oesophagus. A well-marked 

 commissure passes from the upper ganglion over the oesophagus to the 

 left cerebral ganglion, while the lower one is similarly connected 

 with the right cerebral ganglion by a commissure passing under 

 the oesophagus. A commissural ring is consequently formed round 

 the beginning of the oesophagus. 



Only a single salivary gland was apparently present : it formed a 

 large compact mass suspended below the crop (Fig. I. S.). 



As in iV'. Caffra the pedal gland (Fig. I. P.) is greatly developed : it 

 is a long tube, lying freely in the body cavity, and transversely folded 

 upon itself at a point about two-thirds its length from the opening. 



The genital organs are represented in their natural relationship in 

 Figs. II. and III. The spermatheca arises near the point of sub- 

 division of the hermaphrodite duct, and then passes upwards for a time 

 deeply buried in the latter ; it terminates in a pyriform enlargement. 



There is, of course, no jaw. The radula consists of 66 rows having 

 the formula 19"1"19 ; its extreme length is 16 mm. One half of one of 

 the very oblique rows of teeth is figured in Fig. IV. It will be seen 

 that all the teeth are aculeate ; the twelfth is of particularly large 

 size, while the outermost five are quite rudimentary. 



