1871. J 339 rWilder. 



series of changes through which the adult characteristics are 

 reached." 



On the other hand, Owen based his own nomenclature of the 

 mammalian molar and premolar teeth upon the facts of development ; 

 but Flower (227^), and Moseley and Lankester (282) have pointed 

 out defects in this system, and the latter even hold that "the existence 

 of any homology at all between upper and lower jaw teeth must be 

 denied ; it could only have a theoretical existence in connection with 

 that view of the structure of the vertebrate skull, which placed the 

 upper and lower jaws as homologous parts of a vertebra" (282, 272). 



Now all this has no apparent reference to intermembral homolo- 

 gies, but it must nevertheless be considered before any conclusion 

 can be reached satisfactory to all; are, or are we not, justified in 

 comparing the membra together in that condition in respect to both 

 position and structure, which they present when first forming in the 

 embryo? if not, then the utter 'disagreement between Syntropists 

 and Antitropists will forever remain ; but if we are, then the former 

 must simply eliminate from their train of argument, all such criteria 

 as numerical composition, size, shape and function ; and both must 

 wholly disregard the telical parallelism or antagonism which exists 

 between the corresponding parts of the membra of some animals, and 

 must endeavor to ascertain first the general laws of organization 

 according to which the trunk is formed. 1 



October 4, 1871. 



The President in the chair. Thirty- seven persons present. 



Mr. Alonzo Meserve of Neponset was elected a Resident 

 Member. 



Prof. Louis Agassiz made the following verbal communica- 

 tion : — 



Great doubt has always existed among naturalists as to the method 

 of copulation among Selachians, and there is no definite information 

 on this point. In speaking of the subject it has been assumed that the 

 appendages of the male were used in clasping the female during the 

 act, but no facts are given in regard to the manner of their Use. 

 1 To be concluded. 



