178 
THE VOYAGE OF H.M.S. CHALLENGER. 
the middle and at each end, or have a more or less complete series of holes along 
each side. 
The above description concerns the specimen from Station 188. That obtained at 
the Philippine Islands is considerably smaller, only 85 mm. long, and its colour is darker 
from a greater abundance of slightly larger brownish specks. The odd ambulacrum is 
marked out by a narrow dark line. The specimen agrees in all points with the above 
description, excepting in the size of the papillae, which here are comparatively slightly 
larger, and, above all, in the shape of the buttons. In the speciiiien from Station 188 
the knobbed buttons with six holes are by far the most common. In this individual, 
on the contrary, it is rarer to find these smaller buttons, while the more elongated 
kind with numerous holes are' abundant. Thus, I have found here a whole series of 
transitional forms of buttons from those with six holes to a very elongated, narrow 
form, 0'14 mm. long, with as many as sixteen holes, eight in each row. In the 
longest buttons the knobs almost disappear. Considering the great resemblance in all 
other points, and that such long buttons with numerous holes are not rare even in the 
specimen from Station 188, I think the two forms must be referred to the same 
species, though possibly the smaller form may be considered as a variety. 
Holothuria ocellata, Jaeger, 1833 (PI. VII. fig. 11 ; PI. XVI. fig. 1). 
Habitat . — Station 188, September 10, 1874; lat. 9° 59' S., long. 139° 42' R; depth, 
28 fathoms ; greeu mud ; one specimen. 
There seems to be but little doubt that these animals, brought home from the 
neighbourhood of Torres Strait, are identical with Jaeger’s form found at Celebes. 
The animal, which in the contracted state has a length of about 170 mm. and 
a breadth of 55 mm., is of cylindrical form, rounded anteriorly and slightly more 
tapering posteriorly. The dorsal surface is strongly convex, the ventral almost 
flat or inconsiderably convex. The body is angular along each side on the line 
of junction of the two surfaces, which thus become more distinct from one another. 
The mouth with the retracted tentacles has a ventral position, and the round anus 
is terminal. The anus is surrounded by very small, elongated, conical papillae. The 
whole surface of the body is covered by larger and smaller conical papillae or 
prominences, which do not seem to be retractile ; the largest papillae, about 7 mm. 
long and 4 mm. broad at the base, are situated along the angles of the sides of the 
body, forming a kind of brim along the sides ; those on the ventral surface are slightly 
smaller than the dorsal. Tentacles twenty (1), of unequal size. Pound the closed 
mouth is a series of papillae. Colour in alcohol, whitish, with minute brownish 
specks or dots, which are more crowded along the middle of the ventral surface, 
which is thus darker ; on the dorsal surface the specks are more confluent so as to 
