436 PERCY SLADEN TEUST EXPEDITION. 



crest looks like a saw. Along either side of tlie central ridge runs another row of 

 tubercles of nearly the same size ; round the margin and also scattered among the large 

 tubercles are a moderate number of small ones. The whole dorsal area, both the flat 

 surface and the tubercles, as well as the underside of the mantle, is covered with 

 minute roundish granulations. 



The colour is yellowish white, but on the back are arranged five black areas, which 

 make a striking contrast with the ground-colour. They are not placed symmetrically. 

 One is in front, and two lie on each side but not opposite one another. Kound each area 

 is a ring of a brighter white than the rest of the ground-colour. The tubercles are tipped 

 with the same bright white. The largest of the areas measures 8x6 mm., including the 

 white ring. The tubercles extend over these areas as well as over the white surface, and 

 preserve their white colour ; but in this arrangement also the symmetry is imperfect. 

 One black area contains three white tubercles, three contain one each in the centre, and 

 one contains none at all. The rhinophore-pockets and anal papillae are very hard to see. 

 On the under surface of the mantle is a circuit of not very large white lamellae, each 

 about 3 mm. long. The texture of the integuments is hard and spiculous. 



A few minute pebbles were found with the animal in the bottle. It is probable that 

 it lives on a pebbly bottom, where its black and white coloration, so conspicuous when 

 it is isolated, harmonizes with the surroundings. At Naples I have observed that large 

 and conspicuously mottled specimens of Tethys leporina become invisible when they 

 settle among pebbles. 



The integuments are full of short spicules arranged in bundles, and also of small hard 

 granules of various shapes. Unfortunately the preserving fluid had not penetrated the 

 hard skin, and tl^e internal organs were shrivelled and dried, up. Near the mouth was 

 found a bent tube, and it is jorobable that the buccal parts were of the type found in 

 Doridopsis. A thin tube armed with rows of hooks was no doubt the vas deferens. 



This form bears a remarkable superficial resemblance to Fhyllidiopsis papilligera, 

 Bergh, which was found in the Atlantic (Gulf of Mexico). This difference of habitat 

 makes it improbable that the two animals are specifically the same, and they do not 

 , agree in details, though it must be confessed that if they had been found together the dis- 

 crepancies could be explained away : — (1) P. papilligera is nearly circular (12 X 11 mm.), 

 whereas P. carinata is more elongate (22x15 mm.). (2) Not only are the black areas 

 much fewer in P. carinata (which is not in itself important), but they have a special 

 border which, as preserved, appears bright wiiite and is very noticeable. (3) In 

 P. 'papilligera the dorsal papillae have constricted bases and then swell out into an 

 almost ovate outline; in this animal they have broad bases, a conical outline, blunt 

 tips, and are often flattened laterally. (4) There are no ridges on the back of P. papil- 

 ligera, but in P. carinata a median crest or ridge bearing tubercles is a prominent 

 feature. 



28. Ceratophyllidia grisea, sp. nov. (Plate 25. figs. 3-7.) 



Cf. Ceratophyllidia africana, Eliot, in Proc. Zool. Soc. 1903, vol. i. pp, 250-1. 

 One specimen from Coetivy. It is weU preserved, but much bent ; if straightened it 



