140 OKHAMANDAL MARINE ZOOLOGY REPORT 



are incomplete and have a formula of about 7 + 3. 0. 3 + 7. In the hinder rows 

 the number of teeth increases considerably and in the three specimens examined 

 attained a maximum of 11 + 3. 0. 3 + 11, 12 + 3. 0. 3 + 12, and 15 + 3. 0. 3 + 15 

 respectively. The three innermost teeth are large and hamate, but the base of the 

 first tooth does not project markedly into the rhachis as in some species. The fourth 

 tooth bears a projection not amounting to a hook and there are traces of smaller 

 prominences on the fifth and sixth. The outer teeth are flat plates. 



The other internal organs are much as described by me for PI. ocellatus (I.e.), but 

 the oesophagus on issuing from the buccal mass begins to dilate almost immediately 

 into a long stomach-like pouch, which varies in shape in the different specimens, and 

 is constricted just before it enters the liver. The genitalia are small and appear to be 

 immature or at least not functionally active. The dendritic prostate characteristic 

 of the genus is present, but smaller than in the specimens of PI. ocellatus which I have 

 examined. 



I think these specimens are probably a variety of PI. ceylonicus. They agree 

 with Alder and Hancock's description in most points, but still present differences of 

 some importance, (l) The skin is much smoother and not covered with so many 

 papillae and processes. But such projections often disappear when a soft animal 

 shrinks and contracts in the preserving fluid. (2) The radula is rather broader ; but 

 it is probably variable, and Alder and Hancock do not indicate that they examined 

 more than one specimen. (3) The plum-coloured knobs are not mentioned in their 

 description and must be a peculiarity of this variety. Except for the colour, the dorsal 

 processes in one specimen correspond exactly with Alder and Hancock's account. 



Since PL imperialis, Angas, has purple knobs on the dorsal processes (but only on 

 one pair) it would be natural to refer these specimens to it, but they seem to differ from 

 it in some points more decisively than from PL ceylonicus. (l) PL imperialis is said 

 to have two dorsal ridges which meet in a point behind. The present specimens show 

 no trace of such a ridge. (2) PL imperialis has 5-7 hamate teeth, but in the present 

 specimens the number of hamate teeth is consistently three only. But I should not be 

 surprised to find that PL ceylonicus and PL imperialis pass into one another by gradual 

 modifications. 



PL ocellatus from the Red Sea offers few points of structural difference from 

 PL ceylonicus, but superficially the present specimens do not resemble those sent me 

 by Mr. Crossland. 



Bornella digitata, Adams and Reeve. 



Eliot, Proc. Zool. Soc. 1904, vol. 2, pp. 100-2, and references there quoted; and id. in Journ. 

 ofConchol. 1905, p. 238. 



One specimen from Chindi reef. As preserved, it is colourless, somewhat bent, but 

 about 35 mm. long if straightened out, and stoutly built. The rhinophore sheaths 

 bear three short processes in front and a long one behind. Besides the rhinophore 



