CXX1X 
spines) as an outer covering or integument. The body is globose or 
cylindrical, and a ring of nerve branches issues from the mouth. The 
genus of this class called Synapta are cylindrical in form, the body being 
traversed by an alimentary canal, and the mouth is surrounded by a 
fringe of radiate feelers, which are the ends of the nerve system of the 
animal, and serve the purpose of drawing in its food. A skeleton of 
calcareous plates exists below the tough outer skin, and embedded in 
these plates are curious anchor-like appendages, which protrude through 
the skin, giving a rough or rasp-like appearance to the worm. The 
anchors are used both as an assistance to the Synapta in its movements, 
and for fixing itself in the mud or sand ; they are attached to the anchor- 
plates, and are immovable. The Synapta is common on the coast of 
the south of France, and on other shores of the Mediterannean, also in 
those of the Red Sea. Dr. Herapath mentions the species galliennii as 
being obtained by him at Torquay, England. (Quart J. Microscopy, 
1865.) It is generally found in burrows in the sand, and is difficult to 
collect as a perfect specimen, owing to its dividing into separate pieces 
when handled. ‘The anchor-like spicule and plates appear as very 
brilliant objects when polarised, and I have placed under the microscopes 
specimens of them this evening. 
Mr. SAVILLE-KENT, in reply, said : I have much pleasure, in illustra- 
tion of the paper last communicated, in exhibiting to the society living 
examples of the genus Synapta, dealt with by Mr. Atkins, and also of a 
yet rarer, but closely allied form belonging to the genus Chirodota. 
These specimens were obtained by me a few days since when dredging 
between Kangaroo Point and Ralph’s Bay. This locality I may refer to 
as being remarkably rich in representatives of the same animal class, 
the Echinodermata, no less than thirteen distinct species, including 
members of all five of the leading sections or orders of this interesting 
group having been secured. These embraced three members of the sea- 
cucumber order, or Holothuridea; three varieties of ordinary starfishes, 
or Asteridea; two sorts of brittle stars, or Ophiuridea ; four species of 
sea urchins, or Echinidea; and several examples of feather stars, or 
Comatula, representing the Crinoidea, or fifth order of the class. A 
very remarkable feature is associated with the genus Chirodota, to 
which I would more particularly draw attention. This organism is an 
elongate worm-like animal, of a violet hue, possessing an oral tuft of 
retractile tentacles, as in Synapta, and, like that type, the substance 
of the integument is strengthened by the development within it of 
innumerable calcareous plates. These plates are of a very peculiar form, 
taking the shape of beautifully symmetrical six-spoked wheels, and 
having interspersed among them, at more or less distant intervals, hook- 
like spines, which evidently fulfil the same function as the anchor-like 
spicules of Synapta. The species obtained in the Derwent estuary differs 
from the more familiar European species (Chirodota violacea), in the 
minute structure of the calcafeous ‘‘ wheels,” and in their general 
outline, which more nearly approaches a hexagon than a perfect circle. 
Writing of the European species in his book, ‘‘The Microscope 
and its Revelations,” Dr. Carpenter has characterised Chirodota as 
differing from Synapta in the entire absence of anchoring spicules. 
This diagnosis must, however, evidently be modified with relation 
to the Tasmanian variety. My recent study of living examples 
of these two genera has shown that their method of feeding is precisely 
identical with what obtains in the large and more familiar representa- 
tives of the same group, known as the Sea-cucumbers or Trepangs. The 
manner in which these last-named animals took their food long remained 
a mystery, and was solved by me in connection with specimens culti- 
vated at the Manchester Aquarium in the year 1875. A correspondence 
upon this subject will be found in the pages of Nature for the year 1884, 
