298 F. F. LAIDLAW. 



forms can be recognised. The first of these has a narrow pale yellow border and its ground 

 colour is a greenish-black. The second has a broader orange border and its ground colour 

 is rather a velvety-black. 



Excepting for the above difference it is difficult to find any distinguishing characters. 

 Measurements are of little value owing to the varying degrees of contraction of the several 

 specimens, and the dense pigmentation makes it impossible to determine the arrangement of 

 the eye-spots, especially those of the tentacles, with any degree of accuracy. 



I believe the form with the pale narrow yellow margin is identical with Proceros biiskii 

 of ColLingwood, found by him in Singapore Harbour. In his description [4] he gives the 

 colour of the body as a rich velvety olive-green, but in his figure the body is shown rather 

 as black. The appearance of the margin in his figure of Proceros huskii agrees with that of 

 my specimens. I feel therefore justified in identifying them with Collingwood's species. 



12. Pseudoceros huskii (Collingwood). 



Proceros huskii Collingwood [4], p. 91, PI. I. fig. vi. 



Pseudoceros huskii Lang. Naples Monogr. p. 547. 



Ten specimens from Hulule and Minikoi. 



Length about 22 mm. Breadth about 12 mm. Mouth opening 5 mm. behind anterior 

 margin. Sucker 8 mm. behind mouth. 



Colour black or greenish-black with a narrow pale-yellow margin. Eyes on the tentacles 

 and in a small cluster over the brain; only visible in sections. 



The other eight specimens which have a broad orange margin are I think allied to 

 P. huskii on the one hand and on the other to P. velutinus Lang, a species recorded fi-om 

 Ceylon. I think it advisable to refer them for the present at any rate to a new species 

 under the name of Pseudoceros flavomarginatus. 



13. Pseudoceros flavomarginatus n. sp. 



Eight specimens from Minikoi, Laccadive Group. 



Length about 25 mm. Breadth about 15 mm. Mouth aperture about 5 mm. behind the 

 anterior margin. Sucker about 7 mm. behind the mouth. 



Colour velvety-black with an orange margin about 1'5 mm. wide. 

 Eye-spots occur on the tentacles and over the brain. 



It will be noticed that this species is a little longer than P. huskii and that perhaps 

 the relative position of certain organs is different. But, as already remarked, much importance 

 cannot be attached to measurements. 



VI. Family Prosthiostomidae. 



14. Prosthiostomum elegans sp. n. (PI. XIV. fig. 8, PI. XV. fig. 20). 



A single specimen, dredged off hard sand, at 30 fathoms, in the lagoon of Suvadiva Atoll. 



Length of body about 18 mm., breadth 4-5 mm. Anterior margin rounded, posterior end 

 of the body pointed. 



Colour, in the spirit-specimen, pale primrose-yellow. From immediately behind the level 

 of the brain, on either side of the longitudinal mid-dorsal ridge, extends a row of chocolate- 



