81 
During the long foetal life and tke suckling period two of the 
fiist dentitions get an opportunity of developing to suck an extent 
tkat tke succeeding dentitions do not reack any development at all: 
„Es entkalten nun sekon die einfacken Erontzåkne des Milckgebisses 
gleicksam in nuce eine ganze Reihe von friiherer, durck Abkurzung 
in der Entwickelung verloren gegangener Dentitionen. Man muss 
sick vorstellen, dass gleicksam das Material, das friiker zur Aus- 
bildung vieler rasck kinter einander folgenden Kegelzakne der Rep- 
tilien verwandt wurde, aufgespeickert ist und verwendet wird zum 
langsamen Aufbau eines besser ausgebildeten Zahnes.“ (Entstek. u. 
Formabånd. d. mensckl. Mol. pag. 403—404). Tke need for furtker 
speciali sation makes more or less teetk unite into one “tooth- 
colony.” Tke origin of tke multituberculate tootk is not exaetly 
known, peikaps it contains elements of several tooth-rows, perkaps 
only of one, but laterally displaced. — Neitker is the Osborn no- 
menclature correct. Tke anterior lateral cusp of tke upper molars 
is the first to appear, therefore it must be tke protocone; tke 
posterior lateral must be tke metacone, tke anterior lingual tke 
paracone, tke posterior lingual tke kypocone. In the mandible tke four 
main cusps appear exaetly in tke order demanded by the Osborn tlieory; 
for tke fifth typical cusp tke name pentaconid is proposed, its 
place is not fixed, it appears sometimes on tke anterior border of 
tke tooth (e. g. Marsupialia), sometimes on tke posterier (e. g. 
Primates). 
To these challenges Osborn replied in “The history and 
Homologies of the Human molar Cusps” 1892. There is great 
\ariance betvveen tke palæontological and the embryological evidence 
in the order of cusp-development. The pkylogenetic appearance of 
tke cusps is as follows: I. Protocone and protoconid (Permian). 
II Para- and metacone, para-, meta- and III hypoconid (Triassic, 
Jurassic), IV Entoconid (Cretaceous), V Hypocone and hypoconulid 
(Eocene). Tke ontogenetic series for tke lower teeth is exaetly tke 
same, but on tke upper teetk the paracone appears before tke pro¬ 
tocone in Primates and Marsupialia (Rose), in Ungulata botk para- 
Vidensk. Meddel, fra Dansk naturh. Foren. Bd. 65. 
