THE PHYTOSAURIA OF THE TRIAS i6l 



missing, however — probably no small portion. At the base the 

 spine is thin, not over 5 mm. in thickness, and has a width of 

 43 mm. 



Several forms have been described from the region where these 

 remains were found, all based on more or less fragmentary material.' 

 The indications all point to their distinctness from the form herein 

 described, but as yet not enough is known to warrant its being 

 given a new generic name. The writer expects soon to make a 

 series of thorough collections in the western Trias and hopes to 

 add to the knowledge of this and other forms that are little known. 

 A fuller description of the material here mentioned and a discussion 

 of its relationships will follow. 



All who have worked with the phytosaurs have felt, I am sure, 

 that we have been too zealous in our efforts to place all the frag- 

 ments that have been referred to this group in the various schemes 

 of classification. Too often we have proposed new species and even 

 new genera for a few tooth fragments or a few imperfect limb 

 bones. 



The following list consists of those forms that, in the writer's 

 opinion, have been fairly well established. In the arrangement of 

 these forms no attempt is made to show the genetic relationship. 

 I. Phytosaurus Jaeger^ 



P. cylindricon Jaeger 



In 1861 H. von Meyer attempted to show that P. cylindricon 

 and P. cuhricon Jaeger were in reality described from different 

 regions of the jaw of one individual and that this form was the same 

 as his Belodon kapffi.^ This being the case, the name Phytosaurus 

 has priority, and McGregor has so used it (1906) referring to that 

 genus the forms that had previously been placed in the genus 

 Belodon. The material upon which the genus Phytosaurus was 

 based, however, is in such an exceedingly poor state of preservation 



' For a description of Dolichobrachiu?n gracile Williston, Eubrachiosaurus browni 

 Williston, and Brachybrachiiim brevipes Williston, see Joiir. GeoL, XII (1904), 688-94. 



^ G. F. Jaeger, Uber die fossil Reptilien welche in Wiirttemberg aujgefiinden warden 

 sind. Stuttgart, 1828. 



3 "Reptilien aus dem Stubensandstein und Keuper," Palaeontographica, VII 

 253-346. 



