1897.] NATURAL SCIENCES OF PHILADELPHIA. 509 



Tryon's first paper had been contributed in 1861. He was an 

 indefatigable worker, and gave up his interest in a lucrative busi- 

 ness to devote himself to science. He was most generous in his 

 appreciation and encouragement of others. He started the American 

 Journal of Conchology in 1865, and, in 1879, the Manual of Coneh- 

 ology, which is still issued by the Section founded by him. His 

 business training and strict attention to details of management en- 

 abled him, strange to say, to make both of these unpromising enter- 

 prises yield him a revenue, all of which, with much more, was, on 

 his death, left to his favorite department of the Academy, [n 

 quite a special sense, therefore, his work continues. 



Gabb had been appointed a Jessup Fund student, and was en- 

 gaged in those studies which enabled him to render good service on 

 the Geological Survey of California, and to act as Director of the 

 Survey of San Domingo. The income of the Jessup Fund had be- 

 come available for the assistance of young naturalists in 1860, the 

 first recipient of benefits being Charles Conrad Abbott, then en- 

 gaged in the study of ichthyology, but since celebrated for his grace- 

 ful contributions to the literature of popular natural history. Dur- 

 ing the first years of the existence of the Fund, nearly all the young 

 workers in the Academy, including the subjects of this notice, and 

 several of more mature years, were assisted from the income thereof. 

 The Jessup Fund was then, and continues to be, productive of most 

 desirable results. 



Prominent in this group of aspiring young naturalists were Har- 

 rison Allen and George Henry Horn. It is especially fitting, and, 

 indeed, almost unavoidable, that the services rendered by them to 

 science should be commemorated jointly, as their lives were laid in 

 parallel lines to a singular degree. Horn was born in 1840, Allen 

 one year later ; they were pupils of the Central High School at the 

 same time, classmates and members of the same graduating class in 

 the Medical Department of the University of Pennsylvania; their 

 work in the Academy began about the same time, they were both 

 Jessup Fund students, they served contemporaneously in the medi- 

 cal corps of the army during the closing years of the war ; they were 

 to a limited degree, collaborators in their scientific work ; they each 

 held the office of Corresponding Secretary in the Academy, they 

 were members of the Academy's Standing Committees at the same 

 time; they sat together at the Council Board until their work was 

 done, and they died within ten days of each other — the elder after a 



