176 BULLETIN 15, UNITED STATES NATIONAL MUSEUM, 



Fig. 79.— Ophiocrasis DiCTYDiscA. a-c, X 7; d-g, X 11. a, from above; 6, from helow; c, side 



VIEW OF TWO ARM JOINTS NEAR DISK; d, A YOUNGER .SPECIMEN, FROM ABOVE; f , THE S.\ME, FROM BELOW; 

 /, SIDE VIEW OF THREE ARM JOINTS NEAR DISK; (7, ANOTHER YOUNG SPECIMEN FROM ABOVE, SHOWING 

 THE INEQUALITY OF THE TWO TRIOS OF ARMS. 



