3.38 CEYLON PEARL OYSTER REPORT. 



closed, not distinctly stellate. The tentacles are comparatively large and conical. 

 The foot is very narrow, with its margins approximated in all the specimens. 



The radula consists of 44 rows with no median tooth and about 70 lateral teeth on 

 each side increasing gradually outwards from the centre. The outermost tooth is 

 rudimentary, without a lamina, the 2nd is fringed, the 3rd broad and flattened 

 with a slightly denticulate edge, the 4th normal. 



The penis is armed with comparatively few small, distant, hooked plates which are 

 not found on the glans. The vagina bears four large chitinous hooks arranged in 

 pairs one above the other on opposite sides of the lumen, This species belongs to 

 quite a different group of the genus from that of the two preceding. It appears to be 

 distinct from any described species, though approaching somewhat to P. angustipes, 

 Bgh., from the Antilles. 



Platydoris (?) spinulosa, n. sp. Plate II, figs. 20 to 23 ; Plate III., figs. 1 to 3. 



There is one specimen of an apparently undescribed Dorid from 10 miles north-east 

 of Cheval Paar, which I have provisionally referred to the genus Platydoris, though 

 it differs from it in some particulars. 



Its length is 2 "8 centims., width 1"9 centims., height 0*8 centim. The mantle is 

 wide with straight entire margin, covered above with moderate unequal tubercles 

 placed fairly widely apart on the centre of the back and more closely near the margin, 

 but not crowded anywhere. The largest tubercles lie in an irregular ring, 3 to 4 

 deep, parallel to and some distance from the edge of the mantle, the centre and 

 margin being occupied by smaller tubercles. The tubercles are rounded or slightly 

 conical, spiculose, the ends of the spicules protruding distinctly. There are also 

 larger spicules arranged in reticulating bundles between the tubercles. 



The foot is contracted and rather narrow, the front margin bilaminate and divided. 

 The tentacles are very small, pointed and recognisable with difficulty. 



As to colour, Professor Herdman has made a note in his diary on a specimen from 

 this locality which I think there is little doubt refers to the species in question. 

 " Flat red Doris, 1 inch, spotted with dark purple on under-side, wide mantle." 

 There is little trace of colour remaining, the ground colour is white above and below, 

 and the larger tubercles surrounding the centre of the mantle have each a faint light 

 brown ring, the under-side is rather thickly spotted with darker brown, the spots 

 having a deep nucleus and a fainter halo ; their diameter varies from - 5 millim. to 

 1 '5 millims. The rhinophores are white, the branchiae yellowish, shaded with brown 

 internally at their base, rachides white. The branchia? are 6 in number, triqjinnate, 

 the branches small, the rachides long and thick, joined at the base and each with 

 a median groove exteriorly. The branchial pore is raised, circular but not produced 

 into a tube. The rhinophoral pores are slightly raised. 



The radula (Plate III., figs. 1 to 3) differs somewhat from that usually found in 

 Platydoris on account of the rapid decrease in size inwards of the innermost 14 teeth. 



