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290 Generat Notes. [ March, ; 
darwini) and a crocodile (C. ebertsi) have no hypapophysis, follow- 
ing Ludwig’s! wrong description. 
All reptiles possess the hypapophysis (unteres Schluss-stiick) 
of the atlas, and it is quite injudicious that Ludwig and Koken 
could deny the existence of such an element in an alligator and a 
crocodile from the Tertiary. i 
The matter is very simple. Ludwig described the true hypa- 
pophysis of A. darwini as the centrum of the atlas; the axis centrum 
_ . + the odontoid process as the centrum of the axis. Ludwig says 
= , that the odontoid process of the axis is wanting in C. ebertsi, but 
he describes it. He makes something very remarkable out of its 
separation from the axis. He did not find the hypophysis, and 
therefore he says this element is wanting. 
There is no doubt whatever that the atlas and axis of Alligator 
darwini and Crocodilus ebertsi possessed the same structure as the 
living alligators and crocodiles, 
oe Koken finds similar difficulties in the articulation of the ribs 
a (p. 809). “ Die zum Epistropheus gehörige Rippe ist: bet den 
lebenden Crocodilinen gegabelt und gelenkt (nur mit dem Capi- 
tulum) zwischen Epistropheus und Dens Epistrophei, mehr am 
_ lezteren. : 
“Bei Crocodilus ebertsi ist sie ganz auf den Atlas-K6rper über- 
gegangen, bei Alligator darwini trägt degegen der Epistropheus 
3 die Rippe, bei beiden ist sie einfach. 
ee “Bei Enaliosuchus setzt sich die einfache Rippe an die Dia- 
= > pophyse des Epistropheus, während die Parapophysen keine 
-, Rippen stützen. ; 
“ Bei Teleosaurus ist sie gegabelt und sowohl an Diapophys¢ 
wie Parapophyse inserirt. 7 
“Bei Teleosaurus findet sich ferner ein drittes Rippenpaar, 
-~ welches intervertebral zwischen Atlas-Korper und Epistropheus | 
articulirt.” : 
If these characters are true, we have to abandon the value oA 
| 
: 
: 
Siete, chee 
morphology. But we hope to show that the above statements 
- are wrong or incorrect. 
= L In the living crocodiles the rib of the axis shows the follow- 
ing conditions: : 
__ In Gavialis gangeticus the capitulum of the axis-rib articulates 
only with the centrum of the atlas, There is developed a rudimente 
~ ary diapophysis in the neural arch of both sides. The tuberculum 
_ of the axis rib does not reach that diapophysis, but is probably - 
connected with it by ligament. a 
= _ {nan adult Aligator mississippiensis the capitulum articulates 
1 Ludwig, R. „Fossile Crocodiliden aus der Tertiaerformation des Mainzer Becken, _ 
__ Palaeuntographica. Suppl. mt, Lief. 4 u. 5, Cassel, 1877, pp. 13-14, P- 37- 
