Prof. H. G. Seeley on the Ornithosaurian Pelvis. 243 



by von Meyer Pterodactylus dubius (I c. T. vi. fig. 1 ; also 

 Wagner, Abh. Miinchen, Bd. vi. T. vi. fig. 1, and Bd. viii. 

 t. xvi.). It is the only difficult specimen that I have seen. 

 First the iliac bones are connected with the sacrum and the 

 pubic and ischiac bones are displaced outward to the right 

 and left sides of the body (fig. 2) . On the left side the pubis 



Fiff. 2 



Pterodactylus dubius. (Meyer, /. c. T. vi. fig. 1.) 



and ischium are in natural association. Wagner introduced a 

 division between the bones ( pu and isc) which v. Meyer doe3 

 not draw and which 1 do not find in my own note ; and it 

 seems to me to be introduced from the contour of the displaced 

 pubis seen on the right side. The pubis may be compared 

 with the corresponding element in the os innominatum of 

 Rhamphorhynchus longimanus. In (Pt.) dubius it has the 

 same straight anterior border, with a posterior inclination ; 

 but there is a large wide and deep ventral notch dividing the 

 pubis from the ischium, except in the small connecting 

 symphysial area below the acetabulum. No other specimen 

 shows this notch, and in Rhamphorhynchus and some other 

 genera the corresponding space is covered by a thin ossifica- 

 tion. On the right side are the two prepubic bones with their 

 free expanded median borders approximating and almost in 

 contact, and the narrow stalk of the right bone in near con- 

 tact with the proximal border of the pubis ; but there is no 

 indication of the stalk-like process figured by Quenstedt on 

 either the proximal or distal internal surface of the pubis. 

 Yet if the bones which I regard as prepubic are traced off 



