EEPOET ON THE HOLOTHIJEIOIDEA. 
131 
II. Tentacles fifteen. 
Psolus cataphractus {Stolinus), Selenka, 1868 ; Bell, 1882. Holothuria cuvieria, Cuvier, 
1817. (?) Cuviena cuvieria, Jaeger, 1833. (?) Psolus cuvierius, Semper, 1868. 
Dorsal integument very smooth and stone-hard. Mouth and anus stellate, the latter 
not situated on a conical tail. Pedicels of the sole in three longitudinal series; 
round the sharp margin, which surrounds the sole, is a row of small pedicels 
without supporting terminal plates. Deposits — reticulate cups, which in the 
dorsal integument are more closely crowded and partly grown together so as to 
make it uncommonly hard. 
Habitat . — Australia (Selenka). 
Psolus amhulator (subgenus Hypopsolus), Bell, 1882. 
Body like that in the preceding, without any tail. Each lateral ventral series of 
pedicels composed of five or six rows, and the odd series of about ten rows. 
The very large dorsal scales, which form about six not very regular rows of 
about four or five scales in each, are covered by a rather thick integument, and 
do not imbricate with one another. Five very large triangular scales surround 
the mouth ; the five anal scales are particularly small. Many of the large 
scales have one, two, or rarely three small pores in their integument, which 
communicate with a small pit in the plate itself. Bound the margin the scales 
are small and imbricating. Tentacles unknown. 
Hahitai . — Australia (Bell). 
(IMus. Holm.) One specimen from Australia, which is certainly to be referred to this 
species of Bell ; moreover, as will be seen from the following description, the 
general appearance and organisation of the species examined by me are much 
the same as those in Selenka’s Psolus cataphractus', a resemblance in several 
important respects so striking that there is but little doubt they are identical. 
Thus, further investigations will certainly prove that Psolus cataphractus and 
Psolus amhulator are synonymous. 
The specimen in cpiestion has the following measurements : — length of the sole 37 mm., 
breadth of the sole 12 mm. ; height of the anterior part of the body 17 mm., 
height of the posterior part of the body 8 mm. Thus the animal does not 
attain more than half the size of that examined by Bell. Tentacles fifteen, 
somewhat unequal. Each lateral ambulacrum with three or four rows of 
pedicels ; the unpaired ambulacrum with a broader series of pedicels. The five 
triangular oral valves are very considerable, while the anal valves are particularly 
small, giving to the anus an irregularly stellate aspect. The scales of the back are 
of various shapes, very large and thick, so that there are only four or five between 
the anus and the oral valves, and only about five across the back from brim to 
brim. The brim, or the lower part of the sides, forming the margin of the animal, 
is supported by a number of small scales. The whole back is covered by 
