106 
From the other species of Astrotoma known from New Zealand 
waters, A. Waitei Benham, it is very easily distinguished through 
its much coarser granulation of the disk, through the number of 
armspines (8 in A. Waitei), as also through the rings of hooklets, 
which are divided in many small parts in A. Waitei. 
5. Astvopovpa Wilsoni Bell. 
PI. VI. Figs. 8-9. 
Astroporpa Wilsoni. F. Jeffrey Bell, 1917. British Antarctic (”Terra 
Nova“) Expedition 1910, Echinoderma. Zoology. IV.i. p. 7. 
This species is very closely related to the Australian species. 
A. australiensis, described by H. L. Clark^). Only two characters, 
so far as I can see, distinguish it from the latter species, viz.: the 
grains covering the interradial spaces on the oral side are conical, 
slightly pointed in A. Wilsoni, perfectly smooth (or nearly so) in A. 
australiensis’, the colour of the brown rings alternating with the 
white rings on the arms and the disk are pale brown in A. Wil¬ 
soni, dark brown, and accordingly much more conspicuous, in au¬ 
straliensis. Also the mouth papillæ are perhaps slightly shorter in 
the New Zealand- than in the Australian form. These differences 
are certainly rather small, but, if they prove constant, they may 
well justify regarding the two forms as distinet species. At least, 
it would not be correct to unite them into one species on the basis 
of the material available at present (the two specimens of the New 
Zealand form collected by the ”Terra Nova“ and a few specimens of 
A. australiensis, collected by the author in 1914 in the Australian 
seas). 
Belis statement that there is „a total absence of ornament- 
ation from the plates, both of the arms and disc“ seems rather 
peculiar, since there are, upon the whole, no plates to be dis- 
cerned either on the disc or the arms, only a general covering of 
grains of various character, as clearly set forth by Clark. Also 
the statement that „the armspines are numerous, very delicate, 
with minutely roughened surfaces“ is somewhat remarkable; their 
number amounts to 4—6 (only very exceptionally 7), which would 
1) Scientific Results of the Trawling Expedition of H. M. C. S. "’Thetis“. 
Echinodermata. Mern. Austral. Mus. IV. 1909. p. 547. PI. LIV.o. 
