RECORDS 131 



Mr. Trowbridge also gave a preliminary note on some ex- 

 periments conducted by him on the influence of liquid air tem- 

 peratures on the magnetization of steel and iron. 



Adjourned. 



F. L. Tufts, 



Secretary 



SECTION OF BIOLOGY. 



May 13, 1 90 1. 



Section met at 8:15 P. M., Professor C. L. Bristol presiding. 



The minutes of the last meeting of Section were read and 

 approved. 



The following program was then offered : 



R. Weil, A Contribution to the Problem of the Ear- 

 Bones. 



A. G. Mayer, On the Variation of Snails of the Genus 

 Partida in the Valleys of Tahiti. 



0. S. Strong and 0. E. Doran, A Case of Unilateral 

 Atrophy of the Cerebellum. 



Summary of Papers. 



Dr. Weil's paper was a critical discussion of the theory of 

 the ear-bones, as embodied in the recent articles of Gaupp and 

 Kingsley. Two main contentions were considered : First, that 

 the malleus and incus of mammalia were homologous with the 

 quadrate and articular of lower forms, while the temporo-max- 

 illary articulation is a new formation ; second, that the ossicles 

 of mammalia cannot possibly have descended from those of 

 Sauropsida. The first contention is based upon the embiyonic 

 connection of malleus and incus with the Meckelian bar, upon 

 the embryonic situation of the last anterior to the Eustachian 

 tube, and upon the innervation of the muscle of the malleus by 

 a branch of the trigeminus. Embryonically, however, the mal- 

 leo-incudal complex, in addition to its continuity with the Meck- 

 elian bar, arises from the auditory capsule, which contributes to 

 both malleus and incus, the stroma of the tympanic cavity, con- 



