ELIOT— NUDIBRANCHS. 429 



identified by Bergh. I am of opinion that they both represent varieties of one species 

 which is very common on the east coast of Africa. 



17. Chromodoris quadricolor, Ruppell & Leuckart, var. 

 See Ruppell and Leuckart, Neue Wirbellose Thiere, 1828, p. 31 ; Bergh, Siboga Expeditie, 1905, 

 p. 143 and references there quoted. For Chr. iuieata and Chr. magnifica see Eliot, Proc. Zool. 

 Soc. 1904, vol. i. pp. 396-398. 



One specimen labelled " Passe Honareau, Aldabra." As preserved, it is 25 mm. long, 

 10 mm. higb, and 12 mm. broad. The mantle-margin is about 3 mm. wide in most 

 places, but rather wider before and behind, where it covers the head and foot. The 

 body and foot are somewhat bent, and there can be little donbt that, like many other 

 Chromodorids, the animal is capable of assuming another shape in which the body is 

 lower and flatter, the mantle-margin broader, and the foot longer. 



The colours are black, greyish or yellowish white, and faded orange distributed very 

 much as depicted in Quoy and Gaimard's figure of Boris magnifica. The mantle-edge is 

 marked by a white border ; next to this, on the lower as well as on the upper side, is a 

 broad (3-4 mm.) orange band, and next to the orange band a black band, continuous but 

 of irregular width. The remainder of the dorsal surface is whitish, but traversed by 

 broad, distinct, longitudinal, black lines. At any given point between the rhinophores 

 and branchiae there are about six of these Unes, exclusive of the black band. The median 

 line runs straight from the branchiae to the anterior mantle-margiu, but the others are 

 more or less branched and interrupted. Three of them pass between the rhinophores 

 and two terminate just behind the rhinophores. The rhinophores and branchige are 

 orange : there are orange borders round their pockets, round the foot, and round the 

 genital orifices. The sole of the foot is pale orange, but the sides of the foot and body 

 and the upper surface of the tail are, like the back, whitish but traversed by longitudinal 

 black lines, more regular than the dorsal pattern, but in a few places branched or inter- 

 rupted. There are five on the right side, four on the left, besides the circular black band 

 which (just as on the dorsal surface) adjoins the orange border. 



The surface is smooth and both the integuments and internal membranes are tough 

 and hard to cut. The margins of the rhinophorial pockets are slightly raised, but that 

 of the branchial pocket not at all. The anterior margin of the foot is thickened and 

 slightly grooved. The tentacles, which seem to be invaginable, are represented by round 

 knobs. The branchiae are 15, but possibly one or more of them should be regarded as 

 accessory plumes or branches. They are roughly pyramidal in shape and of difi"erent 

 sizes, set in a circle open behind, the plumes nearer to the opening being smaller than 

 the others. 



The intestines are of a yellowish brown. The buccal mass is large. The labial arma- 

 ture is yellowish and has the appearance of a ring, but consists of two semicircular plates 

 almost in contact. The elements are somewhat variable in shape and size. The majority 

 are rods, swollen near the distal end, generally bent and generally bifid ; but near the 

 edges of the plate they are smaller and sometimes roughly triangular. The radula is 



57* 



