PREFATORY NOTE. 
Tue study of young fishes was one of the early zodlogical interests of Mr. 
Agassiz, and he had published a number of papers ' previous to 1883 when the 
late Prof. C. O. Whitman joined the staff of the Museum of Comparative Zoélogy. 
During a part of the years 1883-1886, Professor Whitman worked upon the 
development of some pelagic fishes both at the Newport Laboratory and at the 
Museum, and some of the results of his studies were published in collaboration 
with Mr. Agassiz in the Proceedings of the American Academy and in the 
Memoirs of the Museum.” 
Though the eleven plates for another part of the Memoirs to be ‘‘devoted 
to cleavage, formation of periblast and the development of the germ ring”’ were 
printed so long ago as October, 1885, the accompanying text was evidently not 
written. 
The plates, however, seem of sufficient importance to warrant their publica- 
tion, and this has been made possible through the kind interest of Prof. R. M. 
Strong of the University of Mississippi, formerly of the University of Chicago. 
Professor Strong carried out a thorough search among Professor Whitman’s 
manuscripts for any records upon the embryology of fishes, and has most kindly 
written a brief introduction. To Professor Strong and to Mrs. C. O. Whitman, 
who most willingly aided him, sincere acknowledgements are tendered. 
SAMUEL HENSHAW. 
1 The development of flounders.< Amer. nat., December, 1876, 10, p. 705—708.—On the young stages 
of some osseous fishes.< Proc. Amer. acad. arts. & sci., October, 1877, 13, p. 117-127, fig. 1-2, pl. 1-2.— 
On the young stages of bony fishes.< Loc. cit., June, 1878, 14, p. 1-25, pl. 3-10.— The development of 
Lepidosteus.< Loc. cit., October, 1878, 14, p. 65-76, pl. 1-5.— On the young stages of some osseous 
fishes. Part III.< Loc. cit., July, 1882, 17, p. 271-303, pl. 1-20. 
2 On the development of some pelagic fish eggs.< Proc. Amer. acad. arts & sci., August, 1884, 20, p. 
23-75, 1 pl— The development of osseous fishes. I. The pelagic stages of young fishes.< Mem. 
M. C. Z., September, 1885, 14, p. 1-56, pl. 1-19— II. The pre-embryonic stages of development. 
Part first. The history of the egg from fertilization to cleavage. < /bid., June, 1889, 14, p. 1-40, pl. 20-31. 
