220 
THE VOYAGE OF H.M.S. CHALLENGER. 
terminating in four groups of teeth, each group composed of several (five to 
seven) teeth. Buttons large, of normal shape, slightly asymmetrical, 
Hahitat. — Navigator Islands (Semper), Mauritius (Haacke, Ludwig). 
Differs from Holothuria vagabunda mainly in the shape of the tables. 
Holothuria strigosa, Selenka, 1867. 
Pedicels all over the body. Tables like those of Holothuria vagabunda. Buttons of 
two kinds — in the dorsal perisome symmetrical smaller ones like those in the 
above mentioned species ; in the ventral, on the contrary, more elongate, 
robust, irregular ones, with as many as twelve minute holes. In the neighbour- 
hood of the pedicels much larger buttons may be found. 
Habitat. — Zanzibar (Selenka), Bed Sea (Ludwig). 
Holothuria farcimen, Selenka, 1867. 
Ventral surface with numerous pedicels ; dorsal surface with thinly scattered papillae. 
The solid tables bear four groups of five teeth each on their top. Buttons mostly 
with five pairs of holes. 
Habitat. — Azores Islands (Selenka). 
The species seems to bear the nearest resemblance to Holothuria difficilis. 
Holothuria captiva, Ludwig, 1875. 
Ventral surface with numerous pedicels; dorsal surface with thinly scattered papillae. 
Disks of the tables well developed, and spire terminating in a great number of 
teeth. Buttons of common shape, though slightly asymmetrical. 
Habitat. — Barbados (Ludwig).* 
Differs from Holothuria difficilis by possessing a smaller calcareous ring and by the 
great number of teeth on the rounded top of the spire. 
(Mus. Holm.) Numerous specimens from Bartholomew. The deposits are comparatively 
large. There are twenty or more teeth on the rounded top of the spire, but 
there are tables with even fewer teeth, in which case the top of the spire is 
truncated, not rounded. The buttons are large, elongate, fusiform, more 
or less obviously curved ; the regularly formed ones have six holes, but I have 
seen buttons with even more holes, or with only two, three, or four. Sometimes 
buttons devoid of holes may be found. As a rule, they are thickest along the 
middle line. The pedicels have perforated plates round the well-developed 
terminal plate ; the papillae have also such plates, as well as strong curved 
rods. Numerous Cuvierian tubes are present. Colour in alcohol, light brown. 
Holothuria curiosa, Ludwig, 1875. 
Ventral surface with pedicels ; dorsal surface with papillae. Tables of varying 
size ; in the larger the disk supports a rudimentary spire composed of four short. 
