44 RECORDS 



respond without exception to strong lines in the sun. On the 

 other hand, so many cases were found where a strong " en- 

 hanced " hne was not marked in the sun by a strong Fraunhofer 

 hne, nor by any Hne in the flash spectrum, that Lockyer's 

 opinion does not seem to be supported. 



F. L. Tufts, 

 Secretary. 



SECTION OF BIOLOGY. 



March io, 1902. 



Section met at 8:20 P. M., Professor Bashford Dean presiding. 



The minutes of the last meeting of Section were read and 

 approved. 



The following program was then offered : 



Henry F. Osborn, The Four Phyla of Titanotheres. 



Bashford Dean, The Early Development of Sharks from 

 A Comparative Standpoint. 



Maurice A. Bigelow, The Cyto logical Phenomena of 

 Maturation and First Cleavage in the Cirriped Egg. 



C. C. Trowbridge, The Effect of the Wind on Bird 

 Migration. 



Summary of Papers. 



Professor Osborn presented some results recently obtained 

 for the U. S. Geological Survey Monograph. The lower Oli- 

 gocene Titanotheres prove to belong to four distinct phyla, to 

 which the prior generic names Titanotheriiivi, Symborodon, 

 Megacerops and Brontotherimn may be applied. The chief dis- 

 tinctions are found to be in the dolichocephalic or brachycephalic 

 form of the skull, in the shape, length, position and mechanical 

 relations of the horns, and in the number and form of the incisor 

 and canine teeth. Each genus obviously had distinctive modes 

 of fighting, locomotion and feeding. TitanotJicriiim extends 

 from the base to the summit of the Lower Oligocene. It is 

 distinguished by its long narrow skull, short horns, powerful 

 canines, vestigial incisors. Megacerops, on the contrary, is 

 broad-skulled, short-horned, with obtuse canines, and with at 

 least one upper incisor. Symborodon is distinguished by the 



