RECORDS 147 



The following program was then offered : 

 H. F. Osborn, Dolichocephaly and Brachycephaly as 

 Dominant Factors in the Skulls of Mammals. 

 F. E. Lloyd, Tetrad-formation in the Rubiaceae. 



Summary of Papers. 



Professor Osborn stated that the proportions of the skull in 

 the lower mammals are no less distinctive than in the races of 

 men. Although confined to the cranium in anthropology, the 

 principles of dolichocephaly, mesaticephaly, and brachycephaly 

 could be applied to the skull (/. e., cranium plus face), and are 

 found to illuminate the whole morphology of the skull and teeth, 

 and in many cases the correlation with other parts of the skel- 

 eton. Dolichopodal and dolichocephalic, brachypodal and 

 brachycephalic types are frequently but not invariably corre- 

 lated, the numerous instances of non-correlation being due to 

 exceptional adaptations in feeding. Apart from its relation to 

 foot structure, skull proportion is, in evolution, progressively in 

 one direction or the other, and is the underlying cause of hun- 

 dreds of cranial and dental characters which have hitherto been 

 described by comparative anatomists without appreciation of 

 their true significance. The generalization was first made by 

 the speaker among the rhinoceroses, was subsequently found to 

 apply with equal force to the Titanotheres, and many other un- 

 gulates, unguiculates, and primates. 



Professor Lloyd gave an account of the so-called tetrad divi- 

 sions of the mother cells of the pollen and embryo-sac, in Cru- 

 cianella (2 species), and Aspenda (i species). Briefly stated, 

 these divisions are heterotypic and homotypic in the sense of 

 Flemming and Strasburger. The pollen and embryo-sac di- 

 visions are homologous. In Criicianella all the megaspores 

 undergo the first embryo-sac mitosis. 



Henry E. Crampton, 



Secretary. 



