| OCR Text |
Show 1904.] FROM EAST AFRICA AND ZANZIBAR. 91 of a loose mass of long, yellow, transparent rods, irregular in shape and often bent. In the two specimens dissected, the radula consists of 30 and 31 rows respectively, and the formula of each row is, as a rule, 10 + 1.1.1 + 10 or more rarely 11 + 1.1.1 + 11. The median tooth is squarish, not very broad, and bears, as a rule, five denticles on the anterior edge, but sometimes only four, while in one specimen there were only three denticles in the hinder rows. The first lateral tooth is large and sickle-shaped. The corner of the basal part projects over the rhachidian tooth and creates a false impression that it is an accessory denticle. The remaining teeth are generally ten, but sometimes an additional rudimentary one at the end of the row raises the number to eleven. They are little more than flat squarish plates, decreasing in size outwards. Only the first of them shows some traces of a hamate shape. All the internal organs are of a deep black colour, which rendered their examination difficult. The blood-gland is large. I was not able to make any satisfactory preparations of the reproductive organs, but the glans seemed to be armed with a dense mass of curved rods. I think this form must be identified with Ar. cristata B., of which, however, no specimen has been described, all that is known of it being Semper's drawing and apparently a few notes. But it is also not improbable that it is a variety of N. nigerrima B., from which it differs externally in little except the absence of any red coloration. The number of branchiae is, as explained, uncertain, but the arrangement shown in Bergh's plate of N. nigerrima is certainly not that of these specimens. On the other hand, the presence of the narrow labial armature is an argument for identity. N em b r o th a cjerulea, sp. n. Four specimens from Sii Island, near Yanga. No notes on the living animal, except that it was blue and had apparently no red or green mottlings. The colour of the freshly-preserved specimens was a fine bright indigo, varying in intensity in different parts. One of the specimens was much lighter than the others and also smaller. The whole of its body and the lighter parts of the other individuals were marked with deep indigo spots. The largest preserved specimen is 43‘5 millimetres long, 18 high, and 12 5 broad. The space from the head to the branchise is 12 mm. and from the branchiae to the end of the tail 22 mm., but the tail is longer in this specimen than in the others. The shape is somewhat like that of Ceratosoma without lobes, as the back rises considerably from the head to the branchiae. The integuments are leathery and not at all transparent. The surface is quite smooth, and there is no indication of a mantle-edge. The rim of the rhinophore-pockets is only slightly raised. The rhino-phores themselves are large, entirely retracted, with 25-30 deep |
