IV CONTENTS. 



PAGE 



XII. Note on (lie Deternnnation of the Law of Propagation of Heat 



in the Interior of a Solid Body. By B. O. Peirce, Jr. 143 

 XIII. Antigeny, or Sexual Dimorphism in Butterflies. By 



Samuel H. Scudder 150 



XIY. Characters of some Little-knoxvn or New Genera of Plants. 



By Asa Gray 159 



XV. Ohserrationes Liche7iologicce, No. 4. Observations on North 

 American and other Lichens. By Edward Tucker- 



max, M.A 166 



XVI. Theory of the Horizontal Photohelio graph, including its Ap- 

 plication to the Determination of the Solar Parallax by 

 Means of Tra?isits of Venus. By Professor William 



Harkness, U. S. X 186 



XVII. On Diamido-sulpliobenzide-dicarhoriic Acid. By Arthur 



Michael and T. H. Xorton 205 



XVIII. Contributions from the Chemical Laboratory of Harvard 

 College : — 



Pccsearches on the Substituted Benzyl Compounds. By 



C. LoRixG Jackson 209 



First Paper. On Certain Substituted Benzylbrom- 



ides. C. LoRiNG Jackson 211 



Second Paper. On Parabrombenzyl Compounds. 



Woodbury Lowery 221 



XIX. Contribution toward the History of the Fluorides of Man- 

 ganese. By W. H. Melville 228 



XX. On some Algce new to the United States. By W. G. Far- 

 low 235 



Description of a New Alga of California. By Professor 



Daniel C. Eaton, of Yale College 245 



XXI. Descriptions of New Species of Plants, with Revisions of Cer- 

 tain Genera. By Sereno Watson 246 



Proceedings 279 



List of the Fellows and Foreign Honorary Members 336 

 Index 343 



