176 
THE YOTAGE OP H.M.S. CHALLENGER. 
of small, very spinous cylindrical papillae, thus stellate in appearance. Ambulacral 
appendages — papillae, rather closely placed all over the body, without any arrangement 
in rows. Deposits — tables with rounded, somewhat irregularly perforated disk and a short 
spire, built up of four rods and one transverse beam, and terminating in a rounded very 
spinous top ; knobbed buttons, mostly with six holes and very often with irregular beams 
joining the tops of several knobs. Besides numerous perforated transverse rods, the 
papillae possess tables near their ends which have the disk perforated by numerous 
holes and the spire drawn out into a very long simple point, communicating to the papillae 
a very rough and spinous aspect. Colour in alcohol — ventral surface whitish inclining to 
yellowish, with some large light brownish spots at the middle ; dorsal surface light brown 
inclining to yellowish on the sides, and with some larger darker spots at the middle. 
Length about 240 mm. 
Habitat . — Station 208, January 17, 1875 ; lat. 11° 37' N., long. 123° 31' E.; depth, 
1 8 fathoms ; blue mud ; one specimen. 
This species is doubtless nearly allied to Semper’s Holothuria aculeata, but -Semper 
does not mention anything about the characteristic tables in the papillae, and therefore 
I must suppose that Holothuria aculeata is devoid of them. Some other differences exist 
which will be stated further on. 
To judge from the single contracted specimen I have at my disposal, the conical 
papillae along the sides of the body are slightly larger than the rest, and the sides them- 
selves slightly thickened. Besides, the dorsal papillae seem generally to be more conical 
than those of the ventral surface, which are like rounded warts. Especially the dorsal 
papillae and the papillae round the anus are obviously spinous to the naked eye, owing 
to the long spire of the tables. Owing to the groups of papillae, the anus acquires a 
stellate aspect. 
The calcareous ring is of the usual shape without posterior prolongations. The 
.Polian vesicle has a length of 35 mm. The madreporic canal is uncommonly large and 
thick, attaining a length of about 40 mm. or more; it contains a network of very fine 
calcareous threads. A thick bundle of long, genital tubes, branched three to four times, 
is situated on the left side of the dorsal mesentery. The respiratory-trees are very well 
developed and branched. 
The calcareous tables (PI. VIII. fig. 1, a,h) attain a height of about OT mm., and 
theii- disks are commonly convex on the inner surface ; the buttons (PI. VIII. fig. l,e, f), 
are about 0‘05 mm. long, and their central knobs are generally larger than the peripheral 
ones. The buttons often have a very asymmetrical appearance owing to the beams which 
join the tops of the knobs. The characteristic tables of the papillae (PI. VIII. fig. 1, c, c^) 
have a large, irregular disk with numerous holes, and measuring as much as 0‘14 mm. in 
diameter; and their spire, attaining a length of 0'36 mm., is built up of four rods which 
become united so as to form a single long, s.traight spine. 
