30 THE NAUTILUS. 
teaching, and entered as a Jessup scholar, under an endowment held 
by the Academy of Natural Sciences of this city. He speedily 
showed great interest in scientific study and pursuit, and immedi- 
ately began original research which has made him prominent in 
scientific circles. His mind was stored with a vast accumulation of 
facts which he so aptly used afterwards in illustrating his lectures. 
Early in life he began the publication of those original investiga- 
tions that soon stamped him as one of America’s foremost biologists. 
Later he was called, by the late Professor Spencer F. Baird, to the 
position of Embryologist to the United States Fish Commission. 
The succeeding years, up till 1886, were spent in investigating 
the development, habits and breeding grounds of the oyster, stur- 
geon and other fishes, and in elaborate investigations bearing on 
these. His published papers on the oyster number about fifteen, 
and contain suggestions whose economic value is only now beginning 
to be recognized. His works and papers on the sturgeons and on 
propagation of the salmon are the most exhaustive upon these par- 
ticular lines of study extant. These have been published in the 
bulletins of the United States Fish Commission, and have attracted 
the attention of American and European scientists. By means 
of Professor Ryder’s method, the great fresh water lakes are now 
annually stocked with many thousand young sturgeon. 
Dr. Ryder, four years ago, made an extended investigation of 
oyster culture at Sea Isle City, and the results of these studies are 
expected to revolutionize oyster culture. 
He proved that oysters could be cultivated by artificial methods 
by starting with the egg, and, under conditions which can be con- 
trolled, and within a prescribed area and cost, that oysters could be 
raised by persons possessing the proper knowledge. He also wrote 
extensively upon the development of cetaceans and other mammals, 
and the thoughts and ideas advanced by him and the line of inves- 
tigation opened up have been seized with avidity by scientists. 
In 1886, he was invited to take the Professorship of Comparative 
Embryology at the University of Pennsylvania, and thereafter, 
although actively engaged in undergraduate and graduate teaching, 
he still was busy with his pen. The Proceedings of the Academy of 
Natural Sciences, of the American Philosophical Society, the Ameri- 
can Naturalist, as well as the most prominent of European journals, 
were enriched by his contributions. Dr. Ryder was a strenuous 
opponent of the Weissmanian school of biological thought, believing, 
