338 Baur, Morphogenie der Wirbelsule der Amnioten. 



separately ossified centrum in certain vertebrae of the Ichthyosaurus, thus 

 aflording ground for deeming them essentially distinct from a true 

 centrum, I have applied the therm hypapophysis" to such inde- 

 pendent inferior ossifications in and from the notochordal capsule, 

 and by that term may be signifieft the sub - notochordal - plates in 

 Archegosaurus , which co-exist with proper hemapophyses" in 

 the tail." 



Dieselben Angaben finden sich in Owen 's Palaeontology. See. 

 Edit. Edinburgh, 1861. 



Fr Archegosaurus schuf Owen eine besondere Ordnung: die der 

 Ganocephala. 



Die erste genauere Mitteilung von Cope ber die Wirbelsule 

 der Batrachier und Reptilien der Permformation von Texas geschah 

 am 5. April 1878 vor der American Philosophical Society, Phila- 

 delphia 1 ). 



p. 510 sagt Cope ber die Wirbel von Clepsydrops (Rept. Order. 

 Pelycosauria.) : There are mostly small intercentra throuhgout the 

 dorsal and caudal series, in the latter prolonged into two processes 

 below, constituting chevron bones." 



p. 522 sagt er ber Cricotus (Batr.): The intercentra are more 

 largely developed than in any other genus, having the form and pro- 

 portions of the centra in the caudal region, and being but little 

 smaller in other portions of the column. In the prepelvic region, the 

 true centra only bear neural arches, which are articulated, and bear 

 short diapophyses at their base. On the caudal region they share the 

 neural arches with the intercentra, while the latter bear the conti- 

 nous chevron bones exclusively." 



p. 524. Trimerorhachis insignis (Batr.). 



The centrum is represented by three cortical ossifications of the 

 chorda-sheath, a median inferior, and two lateral. The lateral pieces 

 are quite distinct from each other, and are in contact with the 

 neurapophyses above, and the posterior border of the median segment 

 in front. The neural arch joins chiefly the lateral elements, but is 

 in slight contact with the lateral summits of the inferior dement. " 



Am Schluss dieser Arbeit stellt Cope folgende Stze auf. p. 530. 



5. That in the primitive land vertebrata of the Permian, the 

 place of the vertebral centrum was oecupied by two elements the 

 centrum and intercentrum. 



6. That the intercentrum, from a position of primary impor- 

 tance, as in Rhachitomus and Trimerorhachis, became reduced, and 

 finally mostly obliterated, but that it remains at the present day in 



1) Cope E. D., Descriptions of extinet Batrachia and Eeptilia from the 

 Permian Formation of Texas. Proc. Am. Philos. Soc. XVII. 101. Palaeont. 

 Bullet. Nr. 29. Vergleiche auch Cope E. D. A new Fauna. Amer. Naturalist. 

 May 1878. p. 328. 



