Dr. J. Anderson on an apparently new Form of Holothuria. 191 
are long, pedunculated, and alternately branched ; and the other 
two are short and divided at their tips. They are all of a pale- 
yellow colour, very pellucid, and are about a fifth of the length 
of the body when it is fully extended, The two short tentacles 
correspond to the two tuberculated rows of feet of the dorsal 
aspect. 
+ The body of the animal is covered with calcareous plates of 
an irregular form, perforated by nearly circular apertures (fig. 4), 
The plates found in the feet of the three ventral rows (fig. 7) are 
spindle-shaped; but they change their form in the feet imme- 
diately surrounding the head (fig. 8), and become in appearance 
very similar to the plates found on the body-skin. The plates 
of the dorsal tubercles and feet (fig. 3) resemble in their irregu- 
larity the plates of the body of the animal; and the same may 
be said of the plates occurring in the tentacles (fig. 6), in which 
they may be found extending to their ultimate divisions, 
The very delicate structure of the feet enabled me to ex- 
amine them microscopically in the living animal; and when 
so examined, a continuous circulation of a minutely granular 
fluid may be seen, the current consisting of two streams—one 
passing along one side of the foot to the sucking-disk, and the 
other flowing back from this structure to the body of the 
animal, 
This little creature evidently belongs to Linnezus’s genus 
Holothuria, which Van der Hoeven has lately revived with the 
following signification :— 
“Feet of twofold structure and figure, some cylindrical, di- 
lated at the tip, usually occurring in the abdomen only, others 
situated on the back, not dilated at the tip, emerging from warts 
on the back. Body cylindrical or flattened in the abdomen.” 
Having only found one specimen of this Holothuria, it would 
be premature, it appears to me, to describe it as a new specics, 
EXPLANATION OF PLATE XI. 
Fig. 1. Holothuria, three times the natural size. 
Fig. 2. Buccal extremity and tentacles, 
Fig. 3, Calcareous plates of dorsal feet. 
Fig. 4. a 3 body-skin. 
Fig. 5. s = dorsal feet near head. 
Fig. 6. ” ” oral tentacles. 
Fig. 7. porhon of yentral foot, showing the form and arrangement of the 
plates. 
Fig, 8. Calcareous plates from feet surrounding the head. 
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