70 
THE VOYAGE OF H.M.S. CHALLENGER. 
The retractor muscles are attached at about the middle of the body. The two bundles of 
the genital organs are composed of simple unbranched tubes. The respiratory trees are 
not very richly provided with branches. 
The integument is thin, pliable, and smooth. The minute x -shaped bodies are very 
scattered, and situated in the exterior layer of the perisoma ; their arms are curved, 
directed outwards, and sometimes even bipartite at their ends. They measure as much as 
0‘06 mm. in diameter. The plates are closely disposed, and vary greatly in form and size. 
Thus, one may find a complete series of developmental stages from x -shaped bodies with 
the arms simple or dichotomously branched, and small irregular plates with a few holes, 
up to large round oval or angular, thick, convex, scale-like plates with numerous holes 
and knobs. These larger plates are composed of several layers, with the upper surface 
convex, almost acquiring an aspect like that of the scales of a Colochirus. The largest 
plates measure as much as 0’6 mm. or more. In the ventral perisome, especially near the 
middle row of pedicels, the plates often seem to be elongate, narrow, with two or three 
longitudinal rows of holes. The pedicels are supported by numerous crowded irregular 
transverse rods or rod-like plates, with a few perforations, and their terminal plates are 
not very well developed. Cucumaria parva is doubtless very nearly related to this 
species, and having found nothing contrary in the description of Ludwig, excepting the 
largeness of the individuals and the anal armature, I was almost inclined to consider them 
to be identical. 
Cucumaria insolens, n. sp. (PI. IV. fig. 5). 
Body subcylindrical, with the anal portion often slightly curved upwards. Tentacles 
ten, of almost equal size. Pedicels of two kinds : larger, completely retractile ones arranged 
in double rows along the three ventral ambulacra, and even distributed on or near the 
dorsal ambulacra ; and considerably smaller (papillae ?) present all over the dorsal surface as 
well as in the anterior and posterior parts of the ventral surface. The integument is thick 
and hard from the presence of three kinds of deposits arranged in several superposed layers. 
The exterior part of the integument is furnished with numerous small cruciform bodies 
with the arms curved and more or less branched (incomplete cups) ; beneath these there is 
a rich layer of large, elongate or oval, thick, knobbed, and perforated buttons with one end 
drawn out into a narrow spinous portion, which is directed obliquely outwards ; interiorly 
densely crowded, small, rounded, more regular buttons with few holes and knobs are to be 
found. The pedicels, the larger as well as the smaller, are strengthened by terminal 
plates and strong, irregular, branched or unbranched slightly perforated rods. Colour in 
alcohol yellowish -grey, often, darker and brownish on the back. Length up to 40 mm. 
Habitat . — Simons Bay ; depth, 10 to 20 fathoms ; numerous individuals. 
This form of Cucumaria is very remarkable, and seems to present a certain relation 
