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Show G80 SIR C. ELIOT ON NUDIBRANCHS [June 10, out about GO mm., breadth about 27 mm. The pattern of yellow and purplish stripes is still very plain, though the colours have faded to white and black. The external and internal characters agree with previous descriptions. The formula of the radula is about 57x65.1.1.1.65 in the longest rows. The rhachidian tooth bears one denticle rather high up on either side of the central cusp and 5-6 rather low down. The first lateral is clumsy in shape, and bears 4-5 minute denticles on its outer edge. The remaining teeth are hamate, with projections behind the base. All except the 10-20 outermost have one or more denticles, often only one, but in this case the tooth never appears bifid. L in g u e l l a c in er e a Farran. (Farran, 1. c. p. 334.) One specimen obtained from Kelaart appears referable to this species. Through the kindness of Prof. Herdman I have also had an opportunity of examining the type specimen preserved in the Museum of Liverpool University. Kelaart's specimen is yellowish grey with darker shades here and there, and very flat and broad. Length 25 mm., breadth 21 mm., height 6 mm., breadth of foot 15 mm. The external characters are as described by Farran, but he does not allude to the narrowness of the branchial lamellae, wThich is remarkable in both specimens. They are about 30 in number, and set on the under side of the mantle so as to form a narrow band 2 or 3 millimetres wide. This band is separated from the mantle-margin by a clear space, and from the side of the body by another clear space as wide as the band itself. These side-lamella? run into the gills, which in places are hardly distinguishable from them. The true gills are about 25 in number and prolonged into a distinct cleft. On each side of the large round mouth there appears to be a process attached to the under side of the tentacular shield. There is a groove in the hinder part of the foot. The jaws are yellow, long and narrow, with several rows of denticles, which are most developed on the masticatory process. In places there are at least eight rows of them, but they are often indistinct. The radula is decayed and very fragile, but there are at least 40 rows of teeth, and perhaps 50 teeth in each row on either side of the rhachis. The central tooth is strongly arched, with a moderately long median cusp and 6 or 7 lateral denticles, of which only the highest is on the side of the central cusp as a rule. The first lateral is lower and broader than the rest, and usually bears 8 rather distinct blunt denticles. The succeeding teeth are hamate, and become taller and slenderer in shape and bear more denticles. In the middle of the half row the number of denticles amounts to 18 or 2 0 ; then it somewhat decreases, and on the outer teeth the denticles are more minute and less distinct; but all the teeth,except the outermost of all, bear traces of serrulation. In the broken condition of the radula, however, it is difficult to be sure which are the outermost teeth. This |