NARRATIVE OF THE CRUISE. 
609 
series parallel with the furrow ; spinelets on the outer part of the plate usually granuli- 
form. Actinostome widely expanded ; large fleshy lip. Enormous compound 
madreporiform body. Numerous pedicellarise, subvalvuliform, on abactiual surface and 
actinal interradial areas. 
“ A very remarkable and abnormal Asterid, the morphological structure of which would 
appear to justify its inclusion in the family Pterasteridse, notwithstanding its very 
different habit, was found at Station 323, in 1900 
fathoms. Pythoncister (fig. 203) is characterised by 
very elongate, flexible, subcarinate rays, which are 
slender and tapering outwardly, but considerably 
swollen or inflated at the base ; this inflation beiim 
further emphasized by a well-defined constriction 
which extends along the interradial line up to the 
dorsocentral aperture. This aperture is closed by 
five triangular fan-like valves, as in Hymenaster 
and its allies. The rays and corresponding radial 
areas of the disk are covered with small regularly 
placed fasciculi of short spinelets each fasciculus 
is enclosed in a membranous sac, and the whole 
arranged in regular obliquely transverse lines 
on either side of the median dorsal line, which 
pass along the side of the ray up to the adambu- 
lacral plates. The armature of the aclambulacral 
plates forms transverse series, the spines being- 
united by membrane into fan-like structures com- 
parable to those in Pteraster. 
“ Brisinga occurs both in the North and South 
Atlantic, and was dredged from a depth of 2400 
fathoms at Station 89, where it was accompanied by 
the genera Lonchotaster and Thoracaster. The 
former is an Archasterid with some affinities to 
Bytaster. The rays however, are but slightly 
longer than the diameter of the disk, and are remarkably tapering, pointed, and sub- 
cylindrical, and, in the specimens preserved in spirit, are in every instance turned back over 
the abactiual area. The marginal plates are short and numerous, recalling those of Lepto- 
pty chaster, excepting that the superior series are well developed. The adambulacral plates 
have a compact and powerful armature ; pedicel lame are large and numerous, especially 
on the actinal interradial areas ; and the madreporiform body is immense. Thoracaster 
is an aberrant member of the Porcellanasteridce, having a large pentagonal disk and 
Fig. 203 . — Pythonaster murrayi, Sladen. Abactiual 
aspect. Three fourths the natural size. 
