352 CEYLON PEARL OYSTER REPORT. 



taken south of Adam's Bridge, 30 fathoms, in March, 1902. Professor HERDMAN notes 

 concerning it : " Olive brown spotted with white, foot paler, little spiky papillae on 

 mantle," accompanying his note with a sketch which shows the living animal in 

 configuration and proportions almost exactly as in the preserved specimen. 



The total length is 2'8 centims., width 1'5 centims., height 07 centim. 



The form of the animal (Plate VI., fig. 6) is an oval, produced anteriorly to form 

 the head. It is very much depressed. The foot is conterminous with the body 

 laterally and posteriorly ; anteriorly it extends beyond the head on either side. 



The branchial slit is situated rather nearer the right side, the margins not closing 

 over the slit. The tentacles and rhinophores are of moderate size, tubular and slit as 

 usual. The eyes are distinctly visible in front of the rhinophores. The surface of the 

 back is dotted with little spiky papillae, simple or compound. The shell (Plate IV., 

 fig. 15) is calcareous, very fragile, white with a slight brownish tinge, striated 

 by growth lines and with a small but well-marked embryonic spine (Plate IV., 

 fig. 16). 



The radula (Plate IV., figs. 13 to 14) has 32 rows of 44-1-44 teeth. The teeth, 

 as is usual in the genus, have two broad spatulate cusps and a small basal denticulation. 

 In the 2nd and 3rd innermost teeth the inner cusp is distinctly larger than the outer ; 

 in the 4th they are about of equal size, and from the 5th outwards the outer cusp is 

 the largest. The nature of the buccal armature was not noted. 



Phyllaplysia pellucida, n. sp. Plate IV., figs. 17 to 21 ; Plate VI., fig. 12. 



There are, in the collection, 2 specimens of a smooth flattened Phyllaplysia from 

 Chilaw Paar, for which I propose the above name. They are of a gelatinous 

 consistency, semi-translucent and colourless. The length of the largest specimen 

 (Plate VI., fig. 12) is 17 centims., width 1'5 centims., height 07 centim. 



The foot is as wide as the body. The head is very much contracted, with short 

 tentacles and rhinophores. The branchial slit, length 6 millims., lies rather nearer 

 the right side, the right margin overlapping the left, except posteriorly, where the 

 slit is open. The surface of the body is smooth. The eyes are not visible in the 

 preserved specimens. 



The radula (Plate IV., figs. 17, 19 to 21) consists of about 30 rows of 30-1-30 teeth. 

 The teeth are of the usual form, with two main cusps and a smaller accessory one. 

 From the 1st to the 10th tooth from the centre the innermost cusp is the largest, 

 and from the llth to the 25th the outermost. The five outermost teeth are slender, 

 curved, and simple. The labial armature (Plate IV., fig. 18) is made up of square 

 rods with denticulate inner margins. 



The shell (Plate V., fig. 1) is of the same form as in Aplysia. It is thin and 

 membranous, with a very slight calcareous layer which comes off at a touch. It 

 measures 7 '8 millims. by 5 '3 millims. An embryonic spine was not noted, but it may 

 have crumbled away. 



