86 
The theory advanced by H. W. Marett Tims 1896 ("On 
the tooth-genesis in the Canidæ”) has the following contents: That 
cusp of the upper carnassial tooth (p? and dp?) of Canidæ which 
according to the Cope-Osborn theory may be the protocone, is much 
smaller than the two secondary cusps (para- and metacone); but 
that is absurd, especially as the small ”"protocone” evidently is a 
cingulum-cusp; but the cingulum is a mammalian addition to the 
reptilian tooth, consequently it can not contain the primitive cusp. 
And by comparing dp? and m? one finds that the latter has a well- 
developed protocone inside the posterior cingulum, but this cusp is 
wanting on dp? which has only three cusps, para- and metacoue 
and a cingulum-cusp. By comparing such forms as Canis aureus 
and Cuon rutilans one finds in the jackal a multitude of accessory 
cusps which are all lacking in the dhole; the cusp torresponding 
with the protocone in the former is totally wanting in the latter. 
The protocone itself being such a variable cusp in closely related 
forms is aåa very serious objection to the trituberculism. — If we 
compare the various species of Canis, we see that the more primi- 
tive a tooth is, the fewer cusps it has; therefore one may expect 
often to find more primitive forms in the tricuspid upper teeth than 
in the lower teeth which are generally quinque-cuspid. — An em- 
bryological examination of the succession of tooth-cusp development 
in the upper jaw of Canis affirms the discovery of Råse and 
Taeker that the paraconid is the first to appear. No trace can 
be found in nature of the supposed rotation of the para- and me- 
tacone. Taking all this together not much is left of the trituber- 
culism. — Some important objections can also be made against 
Forsyth Major's Polybuny Theory. The cusps are not developed at 
the same time, as they should be, if they were equivalent; all the 
Multituberculata have got a dentition so specialised that mammals 
with a more generalized one can by no means be derived from 
them; we know non-multituberculate mammals which are much older 
than the Multituberculata; finally the most primitive forms have 
fewest cusps on their teeth. — We have to look for the reptilian 
