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Proceedings of the Eoyal Society 
siphon extends almost to the margin of the umbrella, and is hut 
slightly conical, with a broad truncated extremity. There is no 
median septum in the branchial cavity. 
The Head is about as broad as the body ; the eyes are rounded, and 
prominent laterally, the spherical lens protruding from the middle 
of each. 
The Arms are unequal, the third being the largest, one quarter 
longer than the body, and about one-third longer than the fourth, 
which is slightly longer than the second, and this than the first, so 
that the order of length is 3, 4, 2, 1. The arms are stout, and taper 
gradually to blunt points. The umbrella extends about halfway up 
the dorsal arms and one-fourth up the ventral arms, its extent being 
intermediate between these extremes in the case of the other arms. 
The suckers are round and prominent, and in many cases show a 
double margin, due to a thin membrane surrounding the thickened 
edge of the sucker ; they commence one sucker’s breadth from 
the oral margin, and become gradually larger and wider apart as far 
as the middle of the arm, where they are one sucker’s breadth apart, 
after which they are smaller and closer, and towards the extremity 
stand in contact. There is no trace of a hectocotylus. 
The Surface of the body appears to have been perfectly smooth ; 
it is covered with torn remains of epithelium, but there are neither 
warts nor cirri. 
The Colour is a pale yellowish-grey, and there are numerous 
reddish-brown chromatophores. 
Habitat. — Off the Rio San Francisco, Brazil (Station 125), pro- 
bably surface. 1 mutilated specimen, sex % 
Japetella diaphana , Hoyle. 
Japetella diaphana, Hoyle, Ann. and Mag. Nat. Hist . , ser. 5, vol. xv. 
p. 232, 1885. 
The Body is gelatinous and semitransparent ; it is ovoid in form, 
and considerably longer than broad. The mantle-opening is very 
wide, extending up behind the eyes on either side. The siphon 
extends two-thirds of the distance to the umbrella-margin, and is 
truncated at the extremity. There is a median septum in the 
branchial cavity. 
The Head is nearly as broad as the body, and the eyes are large 
