678 MR. G. C. ROBSON ON CEPHALOPODA 
Up to the present Sepioloidea appears to be regarded as the 
Australian form of the two Sepiadarian genera, while Sepia- 
darium is considered the Pacific form. We now find that the 
latter extends its range to W. Australia, though not by a typical 
member of the genus. Whether, in the first instance, the 
distinction of the two forms into Pacific and Australian rested 
upon secure and sufficient evidence we camnot say as yet. If the 
investigation of the Cephalopod faunas of these areas upholds 
this distinction, the interest and importance of this species of 
Sepiadarium with Sepioloidea-chavacters, as occurring in the 
distributional area of the other genus, will be increased. 
The structure of the hectocotylus corresponds closely with that 
described by Brock (5) for Sepiadarium. It should be observed 
that the series of transverse ridges or bars (Brock’s ‘‘ Quer- 
balken”) are of such a shape as to suggest the obvious con- 
clusion that they represent the fused bases of the pairs of 
suckers, a proximal member of the morphologically posterior 
row being fused with a distal member of the morphologiealiy 
anterior row. 
1. SEPIADARIUM AURITUM, sp. n. (Text-fig. 1.) 
External appearance.—The animal is small and squat, the 
width of the mantle area being about equal to its length. The 
fins are rather long and ear-shaped, the inferior portion being 
slightly broader than the superior. ‘The mantle-insertion at the 
neck is tolerably broad, while posteriorly the edge of the mantle 
exhibits a very slight concavity. 
There is a very feebly developed interbrachial membrane. 
On the arms the suckers are arranged in two alternating rows, 
save at the distal third, where they become abruptly smaller and 
more irregularly disposed. 
The tentacular arms are provided with a short membrane 
conterminous with the area occupied by the suckers. 
The colour (formalin-preserved specimen) is dull grey, covered 
on the dorsal surface by numerous small round patches of pale 
red or brown and fine black or dark-brown spots. Only the 
latter are continued on to the ventral surface and the arms. The 
patches and spots are found, though more sparsely, upon the fins. 
For character of the hectocotylized arm, v. text-fig. 1, C. 
Dimensions :— 
Mantle, max. length 00. 11:25 mm. 
- max. breadth’ -9°%).\' 0. ea ae 
Wencthror tinsm tees: wn toe. 8°75 
Total length (from apex of mantle 
to interbrachial membrane of 
the weulbia) aeMis)\ sg... a 17 
Length of arms: Ist pair......... 7 
PASC Lape aes es Se 6°8 
9 
7 
