86 ROY L. MOODIE. 



so dass die Homologie zwischen Rippen und Querfortsatze erge- 

 ben wurde. Hoffman (6) glaubt jedqch annehmen zu diirfen, dass 

 dieselben selbstandig ossificiren und daher den Rippen ent- 

 sprechen, obwohl der von Hoffman untersuchte Monitor-Embryo 

 in der Entwickelung schon zuweit vorgeschritten war, um die 

 Trennung der Querfortsatze vom Wirbeln constatiren zu konnen. 

 Diese Trennung kann sichaber sogar an ausgewachsenen Thieren 

 erhalten, wie von mir in drei Fallen und zwar an einem Skelete 

 von Hoplurus, Tropidurus, und Uromastix wahrgenommen wurde. 

 Denn der erste Sacral wirbel besitzt Rippen anstatt der Quer- 

 fortsatze, welche dem Wirbel nicht allein durch eine Naht wie 

 bei den Krokodilen und Schildkroten getrennt werden, sondern 

 mit demselben sogar gelenkig verbunden sind." 



In his contribution to the subject of vertebral assimilation Sie- 

 benrock (7) describes several cases such as he mentions in the 

 above quotation and figures the condition in the sacra of Uro- 

 mastix spinipes Merr. and Lacerta simonyi Steind. where the first 

 sacral vertebra as Siebenrock calls it but which is in reality a 

 posterior dorsal, bears a rib. Cope (8) likewise, mentions such 

 a case as occurring in the vertebral column of Phrynosoma and 

 Siebenrock has found the same condition in that genus. Such a 

 condition, however, cannot be interpreted to mean three sacral 

 vertebrae as Siebenrock believes. The vertebra assimilated is not 

 a morphological sacral but merely a functional one and on that 

 account cannot be called a true sacral. Such a condition as Sie- 

 benrock describes is of frequent occurrence among the other 

 reptiles. The appearance of a rib in this situation is not a very 

 remarkable occurrence since there are ribs in this situation in the 

 primitive vertebrates and the occurrence of this rib in the lizards 

 may confidently be regarded as a persistence of the embryonic 

 condition in which the sacral ribs remain as vestiges. In the 

 sacrum of Lyriocephalus Siebenrock (12) describes a vestige which 

 may be interpreted to be a remnant of the sacral rib. 



A close study of my material clearly shows that there are no 

 sacral ribs in the modern lizards. The ilia are always attached 

 directly to the transverse processes of the two sacral vertebrae. 

 In the young specimen of Chameleon owenii Grey the transverse 

 processes of the two sacral vertebrae are of equal size and are 



