1887.] 227 [Cope. 



men, wliich is almost as large as that of the T. longieollis. If the ilium 

 belongs to the same individual as the sacrum, the latter must belong to 

 the T. longieollis ; but I suspect that the association is accidental. 



The diapophyses for the ilia are on the second, third and fourth sacral 

 vertebra;. The second is directed forwards and upwards, the others back- 

 wards and upwards. There is a large deep fossa (or ? foramen) above 

 the posterior halves of the second and third centra. The coossitied bases 

 of the diapophyses form a thin overhanging ledge. 



8. Tanystroph^us willistoni sp, nov. 



This, the smallest of the species, is represented by an ilium, from which 

 the iscliiadic process has been broken away, and probably by some verte- 

 bra; and other bones. The latter can only be associated with the ilium 

 on account of their appropriate size, since they were found with those of 

 the two other species mingled together in one locality. 



The ilium is at once to be distinguished from those of the species already 

 named, by the equal elevation of the internal and external superior bor- 

 ders of the acetabulum. The latter is as widely open internally as exter- 

 nally, which is not the case with the other species. The external superior 

 border, though more produced than the internal, is not so roof-like as in 

 the others. The anterior process above the pubic process is compressed. 

 The pubic surface is sigmoid in vertical section, even more strongly than 

 in the other species. The superior plate of the ilium is much compressed. 



Width of roof of acetabulum 015 



'• " pubic surface 0095 



Length of " " 008 



The dorsal centrum may be that of a young animal, since the neural canal 

 is larger than in the larger species, and the neural arch is not coossified. 

 The median portion is not so contracted as in the other species, and its 

 section is rounded quadrate. Articular faces a little wider than deep. 



Length of centrum 019 



^. , c , f vertical 008 



Diameters of centrum \ ^ „^„ 



(. transverse 010 



Dedicated to Professor S. W. Williston, of Yale College, the author of 

 numerous important works on vertebrate pala;ontology. 



Remarks. — From the above determinations a close parallelism between 

 the Upper Keuper of Wiirtemberg and New ISIexico may be discovered. In 

 both the genera Belodon and Tanystrophieus are abundant, and the Aeto- 

 saurus of the former is represented by the Typothorax of the latter. This 

 association of such verj" diverse forms is good evidence of general identity 

 of fauna, and is a sufficient basis for asserting taxonomic identity of the 

 formations in the two regions. 



