118 



Dr. J. C. Warren, that, also, having only nineteen ribs, six of 

 which are true, and twenty dorsal vertebrge. (Another individual, 

 since examined, has the twenty pairs of ribs, and five sacral 

 bones.) 



These facts prove, at least, that the number of ribs in a perfect 

 skeleton do not always indicate the number of dorsal vertebrae, 

 and the reverse. 



The number of cubic inches contained in the cranial cavity of 

 the Society's skeleton is three hundred and fifty-four. 



Dr. Shurtleff also exhibited an instrument, constructed by 

 himself, for measuring the capacity of the crania of animals, 

 and presented it to the Society, as a standard measure for 

 future use. 



It consists of a hollow metallic cylinder, three inches in dia- 

 meter, and about fourteen inches in length, of the capacity of 

 exactly one hundred cubic inches. Into this hollow cylinder 

 slides a wooden cylinder nicely adapted with a graduation to 

 hundredths, or cubic inches, marked upon one side. In using 

 the above, the cavity of the skull is first accurately filled with a 

 proper material, such as flax-seed, beans, or shot, and then the 

 material is measured, each cylinder full being one hundred cubic 

 inches. The quantity remaining above the hundreds is ascer- 

 tained by putting it into the measure and introducing the wooden 

 cylinder, the graduation on the side indicating the number of 

 cubic inches less than one hundred. 



Dr. Samuel Cabot, Jr., made some observations concern- 

 ing the supposed identity of Anas penelope and Anas ame- 

 ricana, the European and American widgeons. 



Having had a recent opportunity of dissecting two American 

 widgeons. Dr. C. had observed some peculiarities of structure 

 which seemed to him to forbid the opinion that these birds are 

 identical with the European species. Although, very generally, 

 resembling each other, there are some remarkable differences. 

 The difference in the length of the intestines is greater than ever 

 occurs in birds of the same species. Dr. C. had compared the 

 American species with a specimen of the European bird, also 

 dissected by him ; and he gave the comparative measurement of 

 the different parts. 



