REPORT OjST the HOLOTHURIOIDEA. 
88 
and small hemispheres (PI. YI. fig. 9c) of about the same size as the smaller spheres, 
provided with spines round the rim and on the network which closes the openings 
of those half-spheres. 
Colochiriis australis, Ludwig, 1875 (PL XIV. figs. 5, 6 ; PL VI. fig. 6). 
Habitat . — Port Jackson (Australia) ; 6 to 7 fathoms ; a single specimen. 
Though the individual obtained during the Challenger Expedition deviates in some 
points from the types described by Ludwig, I do not hesitate to consider them as 
identical forms. The animal has a length of about 75 mm. Anteriorly and 
posteriorly the body is distinctly pentangular, but towards its middle the odd 
ambulacrum becomes less distinctly angular. The anal teeth are indistinct. The 
mouth is closed by the usual five valves. The colour is darkish brown, with five lighter 
longitudinal bands, of w'hich the three corresponding to the ventral ambulacra are 
almost yellowfish. The surface of the skin is rough, especially on the dorsum, where 
the scales are much larger. 
The dorsal tubercles or processes are small and not very prominent, some of them 
being of minute size. They are to be found only on the ambulacra, where they form 
a double row anteriorly but are situated in a zigzag line, towards the posterior 
extremity of the body. The pedicels are arranged in a distinct double row along each 
ventral ambulacrum. The base of each pedicel is surrounded by a crown of small 
prominent scales (PL VI. fig. 6cZ), and the dorsal tubercles seem also to be formed by 
such scales, in the middle of which the dorsal ambulacral appendages are situated. 
The scales are much larger in the dorsal perisome, especially along the ambulacra, 
where they form longitudinal series. The largest scales have a diameter of about 4 mm. 
Besides these deposits, numerous more or less irregularly formed, knobbed buttons 
(PL VI. fig. 6a), and scattered reticulate hemispheres (PL VI. fig. 66), are to be found. 
Among the larger buttons, several more finely constructed smaller ones are seen. 
The pedicels have perforated rods and terminal supporting plates. A single Polian 
vesicle and madreporic canal are present. The three ventral pieces of the calcareous 
ring are narrower than the rest. 
Colochirus pijgmcBus, n. sp. (PL IV. fig. 9). 
Body elongate, decreasing posteriorly into a narrower caudal portion, quadrangular or 
rather pentangular. Mouth closed by five projections or valves. Anal portion of the 
body without visible scales and teeth. Ventral surface with three distinct series of 
pedicels, each composed of a double row ; anteriorly and posteriorly the pedicels are 
converted into conical non-retractile processes of about the same size as the pedicels, but 
