EEPORT OX THE HOLOTHURIOIDEA. 
59 
January 21, 1876; lat. 51° 35' S., long. 65° 39' W. ; depth, 70 fathoms; bottom 
temperature, 46°’0 ; sand; one specimen. Station 315, January 26, 27, 28, 1876; 
lat. 51 40 S., long. 5/ 50 depth, 5 to 12 fathoms ; sand and gravel; very 
numerous specimens. Station 316, February 3, 1876; lat. 51° 32' S., long. 58° 6' W. ; 
depth, 4 to 5 fathoms ; mud ; one specimen. 
During his stay at the Falklands, Sir WyTille Thomson ^ paid special attention to this 
very interesting form, and it may be permitted to cite his own words : — “ Adhering to the 
fronds of Macrocystis there were great numbers of an elegant little cucumber-shaped 
sea-slug [Cladodactyla crocea, Lesson), from 80 to 100 mm. in length by 30 mm. 
in width at the widest part, and of a bright saffron-yellow colour. The mouth and 
excretory opening are termiual ; ten long, delicate, branched oval tentacles, more 
resembling in form and attitude those of Ocmis than those of the typical Ciicumarice, 
surround the mouth ; the perisoma is thin and semitransparent, and the muscular bands, 
the radial vessels, and even the internal viscera can be j^lainly seen through it. The 
three anterior ambulacral vessels are approximated, and on these the tentacular feet are 
numerous and well developed, with a sucking-disk supported by a round cribriform 
calcareous plate, or more frecpiently by several wedge-shaped radiating plates arranged in 
the form of a rosette ; and these three ambulacra form together, at all events in the 
female, a special ambulatory surface. 
“ The two ambulacral vessels of the ‘ bivium ’ are also approximated along the back, 
and thus the two interambulacral spaces on the sides of the animal, between the external 
trivial ambulacra and the ambulacra of the bivium, are considerably wider than the other 
three ; consequently, in a transverse section, the ambulacral vessels do not correspond 
with the augles of a regular pentagon, but with those of an irregular figure in which 
three angles are approximated beneath and two above. In the female the tentacular 
feet of the dorsal (bivial) ambulacra are very short ; they are provided with sucking- 
disks, but the calcareous supports of the suckers is very rudimentary, and the tubular 
processes are not apparently fitted for locomotion. In the males there is not so great a 
difference in character between the ambulacra of the trivium and those of the bivium ; 
but the tentacles of the latter seem to be less fully developed in both sexes, and I have 
never happened to see an individual of either sex progressing upon, or adhering by, the 
water-feet of the dorsal canals. 
“ In a very large proportion of the females which I examined, young were closely 
packed in two continuous fringes, adhering to the water-feet of the dorsal ambulacra. 
The young were in all the later stages of growth, and of all sizes from 5 up to 
40 mm. in length ; but all the young attached to one female appeared to be nearly of 
the same age and size. Some of the mothers with older families had a most grotesque 
apj)earance, their bodies entirely hidden by the couple of rows, of a dozen or so each, of 
1 Journ. Linn. Soc. Lond., vol. xiii. 1878, pp. 57-61. 
