CHAP. Iv. ] THE CRUISES OF THE ‘ PORCUPINE’, shes a | 
owing to the position and size of the marginal plates, 
which run up nearly vertically from the side of the 
unusually wide ambulacral groove till they meet the 
edge of the perisom of the dorsal surface. The mar- 
ginal plates are thickly covered with rounded scales 
and bear three rows of spines—one at the upper edge 
(and this series in combination form a fringe round 
the dorsal surface of the star-fish), one near the centre, 
and one a little farther down towards the ventral 
edge. The ambulacral groove is bordered by ob- 
liquely placed combs of spines, short towards the 
apex and centre of the arm, but becoming longer 
towards its base, and forming at the re-entering 
angles between the ambulacral grooves large sin- 
eularly beautiful pads; each plate bearing a double 
row of spines, and each spine having a second short 
spine or scale on the end, an arrangement which 
adds greatly to the richness of the bordering. The 
inner spine of each comb on the side of the ambu- 
lacral groove is longer than the others, and bears 
on the end a little oblong calcareous plate usually 
hanging from it somewhat obliquely like a flag, 
with sometimes a rudiment of a second attached to 
it in a gelatinous sheath, which makes it pro- 
bable that it is an abortive pedicellaria. From 
this character, which is one which cannot escape 
observation, I have called the species ‘ vezillifer.’ 
I know no star-fish in which the ambulacral grooves 
are so wide and the ambulacral tubes so large in pro- 
portion to the size of the animal as in this species. 
‘The dorsal perisom is closely covered with rosette-like 
paxille. The colour is a pale rose, with a tinge of 
buff. The ambulacral tubes, which when the animal 
’ 
