274 
are covered with siender, minute spinules, with a single enlarged 
spine in the middle. 
The madreporite is small, not covered by paxillæ or grains, 
situated a distance of about its own diameter from the marginal 
plates. The papulæ are confined to a narrow belt along the inter- 
radial edge, continuing only halfway out on the arms. — Colour 
of the two, dried specimens light brownish. 
It is evident that this most interesting species belongs to the 
‘"seriventral” group of species, the Sckayeri-gvon^ of Doderlein, 
but representing a more primitive stage than any other species of 
the group hitherto known, on account of the much larger number 
of intermediate plates, the proximal series of which continues 
nearly to the end of the arm. The difference between the present 
species and the numerous species with only a single series of 
intermediate plates along each side continuing only for a short 
distance along the ambulacral furrow is so considerable that it may 
seem really questionable whether it can remain within the genus 
Astropecten. But, on the other hånd, its general appearance is 
typical astropectinid ^). If it ought to form a separate genus (— it 
cannot be referred to any other genus of Astropectinids hitherto 
established —) we should, evidently, unite all the other seriventral 
forms with it. But I do not think it desirable to take this step 
and prefer, therefore, to leave it in Astropecten. 
4. Psilastev acuminatus Sladen. 
Psilaster acuminatus. Sladen. 1888. “Challenger” Asteroidea, p. 225. 
PI. XL.1-2. pi. a:lii.7-8. 
— Farquhar. 1898. Echinoderm Fauna of New 
Zealand. Proc. Linn. Soc. N. S. Wales. p. 310. 
— — Benham. 1909. Scientific Res. N. Z. G. Trawl¬ 
ing Exped. 1907. Echinoderma. Rec. Canterbury 
Mus. 1.2. p. 6. 
H.L. Clark. 1916. Sealilies, Starfishes, etc. Biol. 
Res. „Endeavour“ IV.i. p. 32. 
) It may not be superfluous to point out that, although the two specimens 
are dried, I have been able to confirm that the tubefeet are pointed, 
without a sucking disk. There is then no doubt that it really belongs 
to the Astropectinids. 
