ArT. X V.—OBSERVATIONS ON THE TENTACLES OF THE ECHINUS— 
By THE ReEv. Mytron Maury, D. D. 
Having captured an Kchinus on the shore of the harbor of 
Halifax, I placed him in a basin of sea-water for convenience of 
observation. A plentiful allowance of sea-weeds furnished him 
with vegetable diet, and almost gorgeously decorated his domi- 
cile with coloring such as modern esthetic art delights in. His 
term of residence began at four p.m. At that time his tentacles 
were all entirely pellucid. Having noted this, I left him to 
ramble amid the floral beauty of his new abode. At ten p. m. I 
observed him again. To my surprise, the tentacles presented 
now an altogether different appearance. They were opaque, and 
bore a decided purplish tint. I snipped off a portion of one and 
placed it under the microscope, using an inch objective. The 
accompanying cut (Plate IV, Fig. 1) is copied from the drawing 
which I made of the amputated part. The corrugations indi- 
cated, and the quintuple division of the terminal disc, were 
perfectly distinct. 
Applying the 8th objective, I obtained views represented in 
Plate IV., Figs. 2 and 3. Fig. 2 shews a pair of the corrugations 
on one side of the axis of the tentacle, which axis must be 
imagined as running at right angles to the length of the figure. 
Inside the walls are seen fine radiating muscular fibres which 
contract the organ toward the axis. But of greater interest are 
the contents of the interior of the sections. The dark irregular 
blotches indicate pieces of a purple seaweed which had been 
placed in the basin with the Echinus, while the hooked forms 
irregularly distributed in each and all of the corrugations con- 
vinced me that sponge spicules were present. I had unfortu- 
nately no nitric acid at hand to test them, but their shape and 
genéral appearance would almost identify them. __ 
The question naturally forced itself on my mind, How did 
these materials find their way into the tentacles ? For it was not 
one or one row that presented the recorded appearance, but 
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