oi 
and Hoplaster, Perrier. The last may be omitted from the discussion ; 
and both Bell [6] and Ludwig [29] regard Acodontaster as having no 
generic value. It is with some diffidence that I place our species in 
Perrier’s genus Asterodon, for I have only Hamann’s brief diagnosis 
[21] and Ludwig’s figure of Asterodon singularis to enable me to arrive 
at this conclusion. Bell [6] quotes from Perrier’s (1891) diagnosis of 
Asterodon, from which it appears that some species may have one 
dental spine on each angle, and some species two such spines; and 
he regards Odontaster, Gnathaster, and Asterodon as synonymous, the 
former having priority of nine years. But in 1894 Perrier established 
the genus Goniodon for the New Zealand G. dilatatus, which appears 
from the diagnosis in Bronn, &c., to differ from Asterodon and Odont- 
aster only in the great dilatation of the marginals before their sudden 
decrease in size at the tip of the arm; but, as Loriol showed (1895), 
there are two dental spines at each oral angle. Ludwig (1905, p. 42) 
uses Odontaster for all those forms which possess only a single dental 
spine, and thus includes Verrill’s Acodontaster and Sladen’s Gnathaster 
as synonymous. In the same memoir Ludwig gives an excellent 
photogravure of the lower surface of Asterodon singularis, from which 
it appears that this genus has two dental spines: our species has these 
two spines, as Farquhar noted in 1897. Hence we may, as it appears, 
place our miliaris either in Asterodon or Goniodon ;* but in order 
to include it in the latter genus it would be necessary to emend the 
diagnosis: I therefore prefer to adopt the other alternative. And, 
so far as I can judge, Goniodon is not worthy of generic distinction 
from Asterodon; but into that matter I am insufficiently equipped 
to enter. 
Although Asterodon miliaris is quite abundant off our coasts, yet 
it has never received an adequate description, and the difficulty of 
placing it has arisen from the fact that Gray’s type is so badly damaged 
in the neighbourhood of the mouth that Bell (1893, p. 262) was unable 
to. ascertain whether it is armed with five or ten dental spines. | 
have sent specimens to the British Museum, so that we may look for- 
ward to an authoritative pronouncement as to its generic position in 
the near future. 
General Description. 
The general shape is known from Gray’s figure. Form, a 5-rayed 
star, with large disc, short arms, and rounded concave interbrachial 
areas. The colour is a yellowish-brown. The abactinal plates have 
rounded platforms covered with small, short, rounded tubercles ; the 
plates are slightly separated from one another by papular areas. Those 
plates along the median line of the rays are slightly larger than the 
rest, though this difference is more marked in some specimens than 
in others. This median row extends to the tip, and is Se 
aie woth. faces in Anat. Anz., 1908, P- 358, states Ae “ aa! is in- 
validated by its earlier use iD a molluse”’; and proposes Diplodontias, with 
D. dilatatus as type. 
