24 THE GENETIC RELATIONS OF THE CETACEANS. 
ceans have teeth, while on the other hand, not only the whalebone 
whales, but also many Delphinoids, in old age, are wholly tooth- 
less, while others have only one or two teeth. And still he uses 
the want of teeth in the whalebone whales as a distinctive char- 
acter. And thus I find myself still on the same platform with Dr. 
Brandt as to practice although he appears to differ theoretically. 
The codrdination of the want of tecth with other characters in 
the whalebone whales is invariable for the known forms, and may 
therefore be used as a diagnostic character. The want or pres- 
ence of teeth per se is a character of little importance and of 
extremely varying significance. In the Rhytinids, for example, the 
want of teeth is only of family value; in the walruses, the hyper- 
trophy of the canines and concomitant atrophy or suppression of 
the incisors are also only of family value; in the Artiodactyle Un- 
gulates the want of (upper) incisors indicates less than subordinal 
distinction for one group (Ruminants) and in another case (Pha- 
cocherids) scarcely specific distinction! But when the teeth are 
developed, their structure and relations do afford hints, and most 
suggestive ones, and the significance of similarity is more than 
in ratio to the continuing agreement of teeth of increasingly com- 
plicated structure. 
As to the jaws and the teeth, as well as other parts, ther are, it 
seems to me, as matter of fact, more similar in the Zeuglodonts to 
those of ordinary mammals than are those of the Denticetes or 
the Mysticetes, and they are at the same time coordinated with 
other characters less aberrant; in other words, they are in all 
essential respects more similar to the ordinary mammals than are 
the existing Cetaceans and, therefore, to use the favorite expres- 
sion of Dr. Brandt, ubi plurima nitent, they are, inferentially, 
more nearly allied to and less divergent from the ancestral stem. 
If, however, it is denied* that they are more similar, I will only 
reply that I prefer to = tie the evidence of my senses, and 
r Delphiniden PARSE 
nach meiner Ansicht im Vergleich » mit sa es Schiideln der a E f eigen- 
ziemlich glei anomal u nd bilden zwei ftir den Aufenthalt i im hohen 
m 4 
— aha 
geeignete und 
peel sich als dritter pema ger. zn den Phocaceen hinneigender Schiidelty pus, 
der der Zeuglodonten aeai tate op. cit., 331. 
This passa; ing of my remarks respecting the intermediate “ea of the 
Zeuglodonts introduction to i this article. Theo only « comment tle 
ture shall Pa the form moraa test stion. 
SS Me E BAT t t (less thei deviation from the direct 
J 
