KR 
During the long foetal life and the suckling period two of ihe 
first dentitions get an opportunity of developing to such an extent 
that the succeeding dentitions do not reach any development at all: 
»Es enthalten nun schon die einfachen Frontzåhne des Milchgebisses 
gleichsam in nuce eine ganze Reihe von friherer, durch Abkirzung 
in der Entwickelung verloren gegangener Dentitionen. Man muss 
sich vorstellen, dass gleichsam das Material, das friher zur Aus- 
bildung vieler rasch hinter einander folgenden Kegelzåhne der Rep- 
tilien verwandt wurde, aufgespeichert ist und verwendet wird zum 
langsamen Aufbau eines "besser ausgebildeten Zahnes.” (Entsteh. u. 
Formabånd. d. menschl. Mol. pag. 403—404). The need for further 
Specialisation makes more or less teeth unite into one" ""tooth- 
colony.” The origin of the multituberculate tooth is not exactly 
known, perhaps it contains elements of several tooth-rows, perhaps 
only of one, but laterally displaced. — Neither is the Osborn n0- 
menclature correct. The anterior lateral cusp of the upper molars 
is the first to appear, therefore it must be the protocone; the 
posterior lateral must be the metacone, the anterior lingual the 
Påracone, the posterior lingual the hypocone. In the mandible the four 
main cusps appear exactly in the order demanded by the Osborn theory ; 
for the fifth typical cusp the name pentaconid is proposed, its 
place is not fixed, it appears sometimes on the anterior border of 
the tooth (e. g. Marsupialia), sometimes on the posterier (e. g. 
Primates). 
To these challenges Osborn replied in "The history and 
Homologies of the Human molar Cusps” 1892. There is great 
variance between the palæontological and the embryological evidence 
in the order of cusp-development. The phylogenetic appearance of 
the cusps is as follows: 1. Protocone and protoconid (Permian), 
I Para- and metacone, para-; meta- and III hypoconid (Triassic, 
Jurassic), IV Entoconid (Cretaceous), V Hypocone and hypoconulid 
(Eocene). The ontogenetic series for the lower teeth is exactly the 
Same, but on the upper teeth the paracone appears before the pro- 
tocone in Primates and Marsupialia (Råse), in Ungulata both para- 
Vidensk. Meddel. fra Dansk naturh. Foren. Bd. 65. 6 
