128 
RECORDS OF THE AUSTRALIAN MUSEUM. 
On the OCCURRENCE of a STARFISH in the UPPER 
SILURIAN SERIES of BOWNING, N. S. WALES. 
By R. Etheridge, Junr , Curator. 
Starfish have not so far been recorded from the rich fossiliferous 
deposits of Bowning, nor was I cognisant of their presence in 
those rocks until Mr. John Mitchell presented a specimen to the 
National Collection. 
The rarity of this form of life in the Bowning rocks must plead 
my excuse for describing so fragmentary an example as that now 
referred to. The specimen is interesting, not only on this account, 
but also from the fact that it may possibly belong to one of two 
by no means common genera of Upper Silurian age — Palceocoma , 
Salter {non, D’Orb), or Palasterina , McCoy. 
As now preserved, the Starfish consists of portions of three rays 
and traces of the interbrachial disk, with the actinia] surface ex- 
posed. The ambulacra are deep proximally, but become faint 
distally. The ambulacral plates are not clearly distinguishable, 
but the margins of the valleys are bordered by a row of adambu- 
lacral plates, quadrangular and distinct, although the presence of an 
outer row is questionable. Combs of rigid spines are attached to 
the arm edges, of whatever construction they may be. The mouth 
is very large, strongly pentagonal ; the oral plates large, triangular, 
and apparently of one piece each, instead of two, as should be the 
case in a true Paler, ocoma. The arms are united by a disk broken 
up by a series of anastomosing lines, giving rise to the appearance 
of a polygon al-plated integument when pressed together, but in a 
normal condition squamose, as seen through the oral cavity. From 
the margin of the disk stream fine long spines that in all probability 
covered the whole of the dorsal surface. 
It must be at once admitted that, without a more definite 
knowledge of the ambulacral plates, and in the face of single in- 
stead of double oral plates, the reference of this form to Palceocoma f 
Salter, is open to doubt ; but the presence of the disk with its 
squamose plates, laden with spines, seems to place our fossil nearer 
to that genus than to any other. The only other genera known 
to me that it appears to approach are Edrioaster , Billings ; Schen- 
aster , M. & W. ; and Palasterina , McCoy. As regards the first- 
named,* the form of the arms, and nature of the disk, are 
characters sufficient for separation ; whilst the form of the 
adambulacral plates in the secondf genus are likewise distinct. 
* Canadian Or g. Remains, Dec. iii., 1858, p. 82. 
f Illinois Geol. Survey Report, ii., 1866, p. 277. 
