THE NAUTILUS. 

 DR. JOHN A. RYDER. 



29 



Dr. John Adam Ryder, Professor of Comparative Embryology at 

 the University of Pennsylvania, and one of the most eminent em- 

 bryologists and histologists in the world, died at his residence in 

 Philadelphia, March 26, after a short illness, at the age of 43 years. 

 The immediate cause of his demise was a complication of nervous 

 troubles, which brought on gastric symptoms. Dr. Ryder was a 

 very hard student, and his death was doubtless caused largely by 

 over study. 



JOHN A. KYDER, PH. D. 



Dr. Ryder was born near London, Franklin County, Pennsyl- 

 vania, in 1852. He received a common school education and en- 

 tered an academy, where his educational course was interrupted by 

 financial reverses to his father. He then adopted his life work 



