1892.] natural sciences of philadelphia. 289 



September 6. 

 Dr. Geo. H. Horn iu the chair. 

 Fifteen persons present. 



September 13. 

 Mr. UsELMA C. Smith in the chair. 

 Thirty persons present. 



On the Foramen viagnum of the Common Porpoise, and on a 

 Human Lower Jaw of unusual size. — Dr. Harrison Allen 

 invited attention to two skulls of the common porpoise (^Tursiop 

 tursio) and demonstrated that the foramen magnum in both speci- 

 mens received no portion of the basi-occipital bone. The exoccipi- 

 tal bones meet in the median line and the posterior border of the 

 basi-occipital bone lies fully one-half an inch in advance of the 

 foramen. The arrangement of i)arts thus proved to be an excep- 

 tion to the general statement admitted by leading authorities, 

 namely, that the Mammalia are characterized by the lower border 

 of the foramen magnum being foimed by the basi-occipital element, 

 and by the occipital condyle not being composed entirely by the 

 exoccipital. 



Dr. Allen also invited attention to a human lower jaw of unusual 

 size from the Sandwich Islands. As compared with the lower jaw 

 of an English skull the following measurements will prove of 

 interest. 



Sandwich Islands. England. 



INCHES. INCHtS. 



Height of ascending ramus 3? 2? 



Width of ascending ramus Its I5 



5 



2 



_8_ 

 10 



Length of horizontal i-amus 3 2t; 



Goniosymphysal length 41 3° 



Width of horizontal ramus at 



first bicuspid Its ^ts 



Width of horizontal ramus 



opposite last molar ItV 1 



Symphysal height li Ij 



Coronoid height i 



Interironial width 3? 3? 



Condyloid height "z ? 



fr^ 



It will be thus seen that the greatest contrasts in size between an 

 average bone and the one exhibited are to be found in the rami, 

 and the least contrasts, and in most features none at all, in the pro- 

 portions of the processes and iu the width between the angles. 



