1849.] 145 



January 9th, 1849. 

 Mr. AsHMEAD in the Chair. 



Letters were read from Dr. B. F. Shumard, dated Louisville, Ken- 

 tucky, November 20, 184S, and Dr. L. P. Yandell, of same date, 

 severally acknowledging the receipt of their notices of election as 

 Correspondents. 



A letter was read from H. Smith, M. D., dated St. James' Place, 

 London, 1st December, 1848, proposing exchanges of Reptilia with 

 the Academy, and transmitting a list of those in his possession. Re- 

 ferred to the Curators. 



Prof. H. D. Rogers stated that his views of the formation of moun- 

 tain ridges by the upheaving of the crust of the earth I'rom subterranean 

 causes, had been amply confirmed in a tour to Europe, which he 

 recently made for that ])ur])ose. 



Dr. Leidy offered the following observations on the existence of the 

 intermaxillary bone in the embryo of the human subject: 



The immortal Goethe, I believe, was the first to point out the existence of the 

 OS intermaxillare in the human subject, but it has only been observed in an 

 abnormal condition, or where there has been an arrest of development in con- 

 nection with some cases of hare-lip; and the period of life in which it is found 

 as a distinct piece, and its exact limits, have not yet been accurately determined.. 

 The universality of the presence of the os intermaxillare in all animals below 

 man, its presence as a distinct piece in an abnormal, condition in man, always 

 defined by a lateral fissure which characterizes it as the incisive bone, and the 

 uniform existence of a transverse fissure behind the incisive alveoli of the os 

 maxillare superius of the human foetus at birth, have led many anatomists to 

 suspect its normal and independent existence in the embryotic condition of man 

 at an earlier period than it has been sought for. 



As the negro in his anatomical characters is not so far removed from the 

 embryological condition as the white, it is to be presumed that the intermaxillary 

 bone would remain longer distinct; and under such an impression I have several 

 times desired medical students, from our Southern States, whose opportunities of 

 investigating the anatomy of the negro are frequent, to make this a subject of 

 inquiry. Such an opinion cannot be considered unworthy of attention, when it 

 is recollected that Tschudi mentions the existence of a true os interparietale, as 

 a constant condition, in certain branches of the aboriginal inhabitants of Peru, 

 the Chinchas, Aymaras and Huancas. 



Recently having had an opportunity of examining several human embryos, in 

 one of them I was fortunate enough to detect the intermaxillary bone as a dis- 

 tinct and independent piece. This embryo measured one inch and eleven 

 lines from heel to vertex, arid I presumed it to be about nine or ten weeks old. 

 In it ossification had already advanced in the superior maxillary and inter- 



rROCEED. ACAD. NAT. SCI. OF FHILAPELPHIA. — VOL. IV. XO. VII. 21 



