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Show 90 SIR C. ELIOT ON NUDIBRANCHS [May 17, generally rather sombre but gorgeous, a prevalent tint being very dark green or blue with brilliant lighter markings. The gills are few (3-5), but large and strong. The hermaphrodite gland is as usual, and not collected into globules. A very narrow labial armature is present in some species, but usually there is none. The radula is never very wide and sometimes is very narrow, consisting of a median plate with from three to twelve laterals, of which the first is large and hamate and the rest plate-like. The species are not all equally well known, all our information as to N. morosa and cristata coming hitherto from drawings by Semper. It would appear, however, that some of my specimens should be referred to the latter species. JV. nigerrirna, kubaryana, and cristata have a fairly broad radula, with about twelve laterals, and are distinguished by their dark coloration. They are evidently closely related, and may prove to be merely varieties, including IV. morosa. N. gracilis, diaphana, gratiosa, and affinis are lighter in colour, and have a narr ow radula with only three or four laterals. JVembrotha is recorded from the Indo-Pacific and West Coast of Mexico. It is fairly common on the East Coast of Africa. N em b r o th a c r i s t a t a B. [? = JV. nigerrirna, var.] (Plate IY. f i g . 2 . ) [Bergh, S. R. xi. p. 458, pi. xxxiii. fig. 6.] Three specimens from the East Coast of Zanzibar. The living animals are described as having a sloping back, long tail, and narrow foot, somewhat like Ceratosovia. The texture was soft, and the colour a very dark but brilliant green with black spots, and also narrow stripes of brighter and lighter green. The gills were counted as five, and the rlrinophore-pockets were raised. The measurements of the largest alcoholic specimen are : length 54 millimetres, breadth 15, height of body 13, height of branchiae above body 8. The texture has become hard and wrinkled, the animals having evidently been strongly contracted. The main stem of the gills is very thick, strong, and muscular, so that it almost forms a valve to protect the pinnse as in Votodoris. The anterior plume is distinct and separate, but the lateral pairs are almost confluent, and it is consequently hard to say where one begins and the other ends, or whether the total number of branchiae should be reckoned as three, four, or five. The rhinophores are not very large and are completely retracted within smooth projecting sheaths about 2-5 mm. high. The foot is narrow. The relations of the external mouth-parts are much obscured and distorted by the strong contraction which has affected the whole anterior portion of the body, but it appears probable that the foot is grooved and notched with the upper lamina attached to the corners of the mouth, and that the tentacles are horizontal ridges. There is a very narrow labial armature, about half a millimetre wide and hardly visible to the naked eye. It appears to form a complete ring, and is composed |