NATIONAL ACADEMY OF SCIENCES. 



Volume X. 



FOURTH MEMOIR. 



PHORONIS ARCHITECT A: 



ITS LIFE HISTORY, ANATOMY, AND BREEDING HABITS. 



BY 



WILLIAM KEITH BROOKS, LL. D., 



Henry Walters Professor of Zoology in the Johns Hopkins University, 



AND 



RHEINART PARKER COWLES, Ph. D., 



Adam T. Bruce Fellow in the Johns Hopkins University. 



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