DORIDORIDES GARDINERI. 283 
late tips. Near the end of the row they appear thin and 
filamentous, possibly because they have become worn or folded 
on themselves. The radula (fig. 5, a) consists of about 
twenty-six rows, one or two of which are imperfectly deve- 
loped and shadowy, with a constant formula of 4.1.4.1 The 
teeth are neatly arranged in a close-fitting mosaic. The base 
of the large median tooth, which is arched and hollowed out 
behind, is nearly twice as broad as all the four laterals 
together. It bears a single cusp, large and only slightly bent 
downwards (fig. 5, b). The first lateral (fig. 5, c) is about 
three fifths the length of the median tooth but only a quarter 
of its breadth, with a single hamate cusp. The second and 
third laterals are similar but slightly smaller and more bent. 
The outermost tooth (fig. 5,d) is considerably smaller but 
more erect and stands up conspicuously at either end of the 
row. ‘There are two salivary glands ; their distal portions are 
expanded and spread over the genitalia and stomach. The left 
is much larger than the right. The remaining portion of each 
gland is band-like and terminates in a long thin duct which 
passes through the nerve collar and enters the posterior part 
of the buccal mass. Several glands, probably ptyaline, open 
into the buccal cavity, but they are embedded in the wall of 
the cavity and are not visible on its outer surface. 
The cesophagus (fig. 6, a@) is not long, and leads straight 
into the stomach, which is divided into two parts (fig. 6, b 
and ce) by a constriction more marked on the right than on 
the left side. There is no structural difference in the walls 
of these two divisions, and neither contains any spines or 
plates, but as the hepatic ducts all open into the second 
division, the first should perhaps be regarded as a dilatation 
radula, which was disarranged and in confusion, was estimated to contain 
13 teeth in each row (i.e.6+1-+6). But these differences cannot be 
regarded as specific unless shown to be certain and constant. In Tritonia 
the number of rows of denticles in the jaw varies in several species, and the 
formula of the radula in the original specimen was doubtful. The shape of 
the teeth is the same. 
1 See footnote above. 
