NOVA SCOTIAN ECHINODERMATA.—HONEYMAN, 
ho 
Or 
Or 
The third order is Asteroidea. 
Like the Crinoidea, this is a very ancient order in Nova Scotia. 
One of our first Arisaig fossils was Palwaster-parviusculus. 
Billings. This t¢ny aster is in a boulder found near Arisaig Pier. 
We cannot locate it exactly. It is doubtless as old as the Clinton 
ledge, from which we have the best Crinoidea in our Museum— 
“ Arisaig Collection.” Its size equals that of the youngest of the 
“Common Starfish ” in our suite of specimens. This is half inch. 
It is figured and described in Dawson’s Acadian Geology, pp. 
597-8. It has five rays, and shows the under side; two of the 
rays are defective. We quote from Nicholson’s Geology a de- 
scription of the Starfish, page 164 :— 
The body is star-shaped or pentagonal and consists of a central 
body or “dise,’ surrounded by five or more lobes or “ arms,” 
which radiate from the body, are hollow and contain prolonga- 
tions of the viscera. The mouth is inferior and central in posi- 
tion, the arms either central or dorsal. The skeleton is composed 
of a vast number of calcareous plates or ossicula, united together 
by the coriaceous perisome, so as to form a species of chain 
armour. Besides these the integument is abundantly supplied 
with spines, tubercules and “ pedicellariz.” lastly, the radiating 
ambulacral vessels run underneath a species of internal skeleton, 
occupying the axis of each arm and composed of a great number 
of bilateral “ vertebral,” or calcareous plates, which are movably 
articulated to one another and are provided with special muscles 
by which they are brought together or drawn apart.” Our coin- 
mon species is Asterias vulgaris. This attains to a large size. 
One of our Museum specimens measures 17 inches. This has 
five rays. Of another species—Asterias polaris—we have two 
specimens having six rays. The size of these is 12 inches. When 
devouring a mussel or oyster they bring the disc and mouth to 
the juncture of the valves, clasp the valves with their rays, and 
then deliberately raise the body, opening the valves and extract- 
ing the inmate by suction. We have witnessed the operation in 
our aquarium, where we had young star fish, and small mussels 
placed together. In the United States department of the Fish- 
