RECORDS OF W.A. MUSEUM. 
[123 
4(3+4) and sixteen of the eighteen IIIBr. series 4 (3 +4) ; this 
would indicate the species viicrodiscus ; but there are only forly 
arms, and the character of the proximal pinnules and of the cirri is 
identical with that of the proximal pinnules and of the cirri of 
the eighth specimen, which is in every way a typical example of 
elegans. 
In Zygome.tr a comata from the East Indies, Z. ait^yomeda from 
India and Z. punctata from north Australia arid the Aru Islands 
the characters are very stable and variation is reduced to a 
minimum ; but in the larger forms, as in almost all comatulids with 
a very large number of arms, the arm structure becomes more or 
less uncertain and less reliable as a systematic guide than the 
structure of the lower pinnules or of the cirri. 
There appear to be two definite and distinct structural types 
about which all of the large specimens of Zygometra centre, and it 
therefore seems most logical to recognise two species each with a 
definite pinnule and cirrus structure, and a definite average arm 
structure. 
Zygometra multiradiata I believe, from an examination of the 
type in London, to be merely an undeveloped specimen of Z. micro- 
discus. I would now refer to Z . microdiscus the specimens which I 
recorded from northwestern Australia, and from Lewis Island in 
the Dampier Archipelago. 
Fam. : Himerometridae, A. FI. Clark. 
Genus : Amphimetra, A. H. Clark. 
AMPHIMETRA DISCOIDEA, A. H. Clark. 
Amphimetra discoidea, 1911. A. H. Clark, The Recent Crinoids of Australia, p. 766 
ign, A. H. Clark, Ergebnisse der Hamburger sudwest-Australischen 
Forschungsreise 1905, Bd. 3, Lief. 13, s. 459. 1912, A. IT. Clark, The 
Crinoids of the Indian Ocean, p. 112. 
Locality. Between Fremantle and Geraldton. 
Depth. 60-100 fathoms. 
Material. Six specimens. These are all large and well 
developed, the arms being between 185 mm. and 195 mm. long; 
the centrodorsal is from 6 mm. to 8 mm. in diameter, very broad, 
with a flat or more or less convex dorsal pole in the centre of 
