. Echinoderms of Connecticut . FIG. 17. Arbacia punctulata. Side view of young urchin immediately after the metamorphosis. The spines re- maining from the pluteus are in process of absorption. (After Brooks^.) When ready to assume the adult form, the pluteus settles to the bottom, absorbs its larval organs, and by a complicated meta- morphosis assumes the condition of a young urchin (Figs. 17 and 18). The young urchin differs from the adult in having the whole upper surface covered by the plates which will event- ually form only the periproct of the adult, and by the relatively enormous tube-f
. Echinoderms of Connecticut . FIG. 17. Arbacia punctulata. Side view of young urchin immediately after the metamorphosis. The spines re- maining from the pluteus are in process of absorption. (After Brooks^.) When ready to assume the adult form, the pluteus settles to the bottom, absorbs its larval organs, and by a complicated meta- morphosis assumes the condition of a young urchin (Figs. 17 and 18). The young urchin differs from the adult in having the whole upper surface covered by the plates which will event- ually form only the periproct of the adult, and by the relatively enormous tube-feet. The animal is now radially .symmetrical, and creeps about on the sea bottom after the manner of the adult urchin. It feeds upon diatoms and other minute organisms until,
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherhartf, bookyear1912
