318 
THE VOYAGE OE H.M.S. CHALLENGED. 
A species of considerable size, though no, example is complete, probably because 
special care is necessary in preserving specimens in dense tubes. The length of the 
form is about 70 or 80 mm., and the breadth anteriorly 8 '5 mm. 
The head of this species is very similar to that of Nothria ahranchiata, the 
external (short) tentacles and the tentacular cirri being perhaps a little shorter. No 
eyes are visible. 
The dental apparatus (Figs. 74, 75) is dull madder brown. The angle formed by 
fhe posterior appendages with the maxillae is much less than in the former species, so 
Fig. 74. — Maxill® aud dental apparatus of a male specimen of Nothria pycnobranchiata, n. sp.; x 15 diameters. 
Fig. 75. — Maxillae and dental plates of a female example, about the same size as the former. The posterior spathulate plates 
have been bent downward, and therefore are not fully shown ; x 15 diameters. 
Fig. 76. — Ventral view of the mandibles of the latter specimen ; x 15 diameters. 
that the processes are more easily seen from above. A male (Fig. 74) showed consider- 
ably longer maxillse than any of the females (Fig. 75), indeed the whole apparatus had 
a longer antero-posterior diameter. The widening above the base of the maxillse is less 
pronounced. The posterior appendages have a triangular basal part, and a convex 
marginal region. The rounded posterior border has a median notch. The left great 
dental plate presents the usual long anterior fang, which is followed by eight teeth ; the 
right has ten. The left lateral paired plate has eight or nine teeth, and the accessory 
a single tooth (rarely double) ; the unpaired nine teeth. The right lateral possesses 
ten teeth. In the female the maxillse seem to be shorter and broader, but the teeth on 
