56 PROCEEDINGS OF THE ACADEMY OF [1883. 



the desired pieces were detached. It may, therefore, be probable 

 from the fact, that the melting point of copper is aliout 1000° C. to 

 1398°, there was sutiicient heat generated by fii-es, used in above- 

 mentioned method, to smelt the small points of copper attached 

 to the larger masses, and that these people possessing the intelli- 

 gence and quick perception of the Indian races, weie led to notice 

 and utilize it in smelting copper and casting their work. The 

 artistic forms and finish of their copi^er implements, whether cast 

 or hammered, cannot fail to impress the observer that a race of 

 men existed in the earl}' history of our continent, whose origin is 

 enveloped in mystery, and whose skill rivals man of historic times, 

 assisted hy all the inventions of this mighty age of Iron. 



IVie Tritahereular Type of Bivpey-ior 3Iolar Tooth. — Prof. Cope 

 made some observations on the trituberculate type of superior 

 molar tooth among the mammalia. He remarked that it is now 

 apparent that the type of superior molar tooth which predominated 

 during the Puerco epoch was triangular; that is, with two external, 

 and one internal tubercles. Thus of forty-one species of Mammalia 

 of which the superior molars are known, all but four have three 

 tubercles of the crown, tliough of these thirt^'-seven triangular 

 ones, those of three species of Feripti/chus have a small supple- 

 mentary lobe on each side of the median principal inner tubercle. 



This fact is important as indicating the mode of development 

 of the various t^'pes of superior molar teeth, on which we have 

 not heretofore had clear liglit. In the first place, this tyi)e of 

 molar exists to-day only in the insectivorous and carnivorous 

 Marsupialia ; in the Insectivora, and the tubercular molars of such 

 Carnivora as i)ossess them (excei)ting the plantigrades). In the 

 Ungulates the only later forms of it in the Eocene are to be 

 found in the molars of the GorypJwdonfidse of the Wasatch, and 

 Dinocerata of the Bridger Eocenes. In later ei)ochs it is chiefly 

 seen only in the last superior molar. 



It is also evident that the quadritubercular molar is derived 

 from the tritubercular by the addition of a lobe of the inner part 

 of a cingulum of the posterior base of the crown. Transitional 

 states are seen in some of the Peripfi/chidse {Aniaonchus) and in 

 the sectorials of the Pr-ocyonidap. 



The Spinal Chord of Bafrachia and PeptiJia. — Dr. Harrison 

 Allen called attention to the characters furnished by the spinal 

 chord in the systematic study of batrachians and reptiles. In 

 making a i^esume of the researches of Stieda Liideritz, S. H. Gage 

 and J. J. Mason he had formulated the following structural features 

 which may be added to tliose cliaracters already employed by 

 systematists. In batrachians, as illustrated in Bana, Meno- 

 poma and Siren the connective is seen about the central canal 

 to be of unusual development, and in Siren to embrace the entire 

 chord in a conspicuous cortical layer. In addition to these 

 features, connective-tissue corpuscles are sparsely distributed 



