HISTORICAL 19 



laboratory at Newport, R. I. Several stages were described and 

 figured by him in his Revision of 1872- 1874, the six-armed stage 

 (p. 729, Fig. 66), and the very young metamorphosed form three 

 weeks older, with primitive spines and tube feet (p. 734, 735, Figs. 68, 

 69, and Plate V, Fig. 9). A more complete account has been given by 

 Fewkes (1881), working in Agassiz's laboratory, and a more detailed 

 description of the late stages by Agassiz himself (1904, p. 53, and Plates 

 53, 54). Another group of investigators studied the development and 

 metamorphosis o^ Arbacia punctulata at Beaufort, N, C. W. K. Brooks 

 has published these observations together with excellent drawings in 

 his Handbook of Invertebrate ^oology (1882), a laboratory manual written 

 for his students at Beaufort. He has included observations and drawings 

 of his students, Garman and Colton, published in 1883. A. Agassiz has 

 selected the best figures of J. punctulata (Figs. 38-45) for Plate IX of 

 his monograph of 1883 a from both groups of investigators, and figures 

 of ^. lixula (Figs. 20-25; 28-37) from Busch and J. Miiller. 



