MORPHOLOGTOAL METHOD AND EECENT PROGRESS IN ZOOLCX^Y. 583 



Siitisl'actoi'v as is this i'(>sult. it imist be clearly horn in mind that its 

 realization could not .have coni(> about ')ut I'or a knowledge of the 

 animals of the past. And turnino- now to paleontology, it may be said 

 that at the time of our last meeting in this city the scientific world 

 was just l)ecominw- entninc(>d by the promise of unexpected results in 

 the exploration of the American Tertiary beds, then beino- first 0})ened 

 up. The Rocky Mountain district was the area under investigation, 

 and witli this, as with the prog'ress in our knowled^^'e of recent forms, 

 no one livino- was prepared for the discoveries wdiicli shortly came to 

 pass. To consider a concrete case, we may premise^ that study of the 

 placental nuunmals had justified the conclusion that their ancestors 

 nuist have had e(|ual and pentadactyle limbs, a complete ulna and 

 fibula, a com})lete clavicle, and a skull with 44 teeth- nuist have 

 realized, that is, the ])redoniinant term of the living insecti\ora 

 as generally unchn'stood. Who among the zoologists of ourtinu^ does 

 not recall with enthusiasm the revelation which arose from the dis- 

 covery, during these early days, in the Eocene of central North 

 America, of the genc^-a at first desci'ibed as Eo- iwnX JLIohyii.s/ The 

 evidence of the existence, in the locality named, of these 44-toothed 

 peccaries, as they were held to l)e, rend(>red clearer the I'ecords 

 of the later Tertiary deposits of the Old World, which were those of 

 hogs, and, in corrcdation with the facts then known, suggestcnl that 

 the Rocky Mountain area was the home of the ancestral porcine stock, 

 and that in early Tertiary times their descendants must hav(Mnigrated, 

 on the one hand, across the northern l)elt, of wdiich the Aleutian 

 Islands now mark the course, into the Old World, to beget, l)y compli- 

 cation of their teeth, the pigs and hogs; and on the other into central 

 South America, to give rise, ])y mnuerical reduction of t(>eth and toes, 

 to the peccaries, still extant. 



Migration in opposite directions with diversity of modification was 

 the refi'ain of this remarkable find, far-reaching in its m<)r))hological 

 and zoo-geographical effects. Nor can we allude^ with less fervor to 

 the still more striking case of the horses, which proved not merely a 

 similar, though p(M-haj)s a later, migration. l)ut a parallelism of modi- 

 fication in both the Old and New worlds, culminating in the latter in 

 extinction, whereby it became necessary, on the advent of civilized 

 man, to cai'ry l)ack the Old World horse to its ancestral American 

 home. No wonder that this should hav(^ provoked our Huxley to the 

 remark that in it we have the ''demonstrative evidence of the occnr- 

 rencc^ of (W'olution,'' and that the facts of paleontology came to be 

 regarded as certainly not second to those of the fascinating but seduc- 

 tive department of (Mubi-yology, at the time making giant strides. 



I have endeavored thus to ])ietiire that state of zoological science at 

 the time of our last meeting here, and 1 wish now to confine myself to 

 some of the l^roader results since achieved on the morphological side. 



