478 



PEOr. p. M. DUNCAN ON SOME 



distinct, irregularly placed, knob-shaped spines on them, which 

 are not quite globose, having a blunt tip ; they are minutely 

 thorny at the top, and have a rather constricted peduncle and a 

 broadish defined expanded base. The centre of the disk, where 

 the shields do not reach, and the linear interradial spaces bear 

 larger spines, six or seven in the centre and three or more else- 

 where, but all have the same knot -shape and minutely spiny sur- 

 face. Some on the interradial spaces are slightly elongate, and a 

 large one is usually at the margin. The iuterbrachial space below 

 and at the sides is ornamented with several of these spines. The 

 generative plates are large and distinct. The upper surface of 

 the disk contrasts with the skiu-covered iuterbrachial, regions. 

 The mouth-shields and side mouth-shields, although fused and 

 covered, are seen to be large. The distal end of the mouth-shield 

 is globose ; and the side mouth-shields, broad orally, are ornamen- 

 ted by a slender, downward projecting, club-shaped spine, some- 

 times forked close to the generative slit. The side mouth-shields 

 do not unite externally, but only reach the under arm-plate. 



The jaws are short, rather separate, parallel, rather swollen 

 high up in the region of the upper tentacle, where there is a 

 rounded spiny process. There are ten tooth-papillae on an oval 

 mass ; and the angle is large, and projects rather downwards. The 

 tentacles are long and large. 



The under arm-plates are covered with a delicate skin ; but the 

 plates are visible and are separate, rather hexagonal, broadest 

 without, where there is a notch, and angular orally, the line within 

 being slightly notched. The outer angles are rounded, and the 

 sides slope in straight. There appears to be a median depression, 

 and the outer angles are swollen. 



The skin on the upper arm-plates usually hides them, but they 

 are rounded rather angularly distally. A series of solitary 

 median large bosses passes down the arm, and two or three smaller 

 ones are in a transverse line between them. These last do not 

 exist at the tip, where the large boss is very distinct. 



The side arm-plates have the characters of those of the genus ; 

 the}'' are minutely granular at the sides and swollen, but there is 

 no special ornamentation or keeling. The upper spine of the 

 five is small and rugged, the next is larger and longer and often 

 spiculate, the third is the largest and is denticulate within, and 

 the others become strong hooks with the points looking orally down 

 the arm. There are no tentacle-scales, and the long tentacles 



