20 THE AMERICAN MONTHLY [Jan 
arms. The fertilized ova are set free as barrel-shaped em- 
bryos which acquire four encircling bands of cilia. Next 
appear a few minute calcareous plates within this embryo, 
forming as it were, a tiny cask set upon a tiny stalk. 
Free swimming life being now almost ended, a disc 
containing a perforated plate appears on the lower ex- 
tremity of the stalk ; and by this attachment is made to 
any object that happens to be in the way. The soft, bar- 
rel-shaped mass of the swimming larva has now shrunk 
and adapted itself to the form of the enclosed calcareous 
skeleton, and the creature is fairly launched upon the stalk- 
ed and anchored period of its life. In this stage the 
skeleton is made up of a basal plate, rooting the animal 
to its host, a considerable number of joints set end to end 
forming a stalk upon which is seated the cup-shaped 
frame-work of the body, consisting of two circles of mee 
perforated plates, respectively the ‘‘basals” and ‘‘orals.”’ 
The former form the base of the cup, and the latter the 
upper ones. Growth after this is rapid ; other circles of 
plates appear, the ten arms proceed from one of the cir- 
cles, the top joint enlarges into a plate-like structure and 
develops claw-like jointed organs, the cirri. The body 
breaks off from its stalk and becomes free to creep among 
the rocks at will, or swim gracefully with rythmic beats 
of its long feather-like arms. Special interest attaches 
to this beautiful creature from tht great part played by 
its relations, if not its ancestors, which lived during for- 
mer periods of the earth’s history, for the Encrinites, 
whose remains contributed_to greatly build up the huge 
masses of our mountain limestones, were but gigantic 
Pentacrinoids of structure practically identical with the 
stalked larva of the Antedon (Hornell), Dr. Carpenter’s 
“Microscope” has a good plate of the rosy feather-star. 
My remarks have been largely taken from “Gosse’’ and 
from Cassells “Natural History.” also from Hornell’s 
“Journal of Marine Zoology.” 
