214 



Transactionn. 



form plate is fairly large, somewhat convex, finely striated, and situated 

 almost on a median interradial line. The skin on the dorsal surface is red, 

 the marginal plates purplish-grey, the paxillae grey, the madreporiform 

 plate white, and the oral surface creamy-white. When the specimen had 

 been placed in alcohol for a short time and then dried it became brownish- 

 grey above and yellc wish-grey beneath. 



The unique type specimen is at Victoria College, Wellington. 



Amphiura arenaria sp. nov. 



The disc is pentagonal, with only the slightest constrictions in the inter- 



brachial spaces ; it is about 10 mm. in diameter. The arms are very long 



and slender, tapering towards the extremities ; about 180 mm. in length, 



and 1-5 mm. wide near the disc without the spines. 



The scaling on the dorsal surface of the disc is very irregular ; on the 



outer sides of the radial shields and on the margins of the disc the scales 



are imbricating and larger than elsewhere ; 

 at the middle parts of the disc and in the 

 iuterbrachial spaces remote from the margins 

 the scales are small, roundish, and isolated, 

 closer together in some specimens than in 

 others. One scale in the centre is usually 

 larger than those around it. The radial 

 shields are very long, truncated without, 

 where they meet, and tapering to a rounded 

 point within ; the scales between them are 

 elliptical, isolated, and rather larger than 

 the general scaling, being about the same 

 size as those on the outside edges of the 

 radial shields. The scaling on the oral sur- 

 face is very fine. 



There are 2 stout squarish mouth - pa- 

 pillae at the apex of the mouth - angle, 

 and 1 rather long, rounded, cylindrical, and 

 tapering on each side. The mouth-shields 

 are small, oval, leaf-shaped, with a small 



point within and a longer one without, and the madreporiform plate is 



very large, irregularly round, much swollen, and very conspicuous. The 



side mouth-shields are rather large, triangular, with long angles and re- 



enteringly curved sides ; they do not 



meet within. The under arm-plates are 



squarish, with rounded angles, those 



near the mouth being somewhat longer 



than broad. The upper arm -plates 



are broader than long, rounded within, 



narrowing and sometimes truncated 



mthout, except near the disc, where 



they are sometimes squarish. The side 



arm-plates bear 7 rounded, cylindrical, 



pointed spines near the disc, decreasing 



in number outwards to 3 towards the 



extremities of the arms ; the uppermost spine stands vertically on the 



arm. The tentacle-pores have 1 small, leaf -like scale ; some have 2. Some 



young specimens have imbricating scales over the whole of the dorsal surface 



Fig. 1. — Amphitirn arenaria. 

 Dorsal .shields ; x 0. 



Fig. 2. — Amphiura arenaria. 

 Mouth-plates; x 9. 



