40G MR. A. SMITH WOODWARD ON THE [June 29, 



other cranial elements in a more or less well-preserved state. Among 

 the latter are two long bones with expanded extremities, lying 

 lengthwise, one on either side of the basi- and presphenoids ; and 

 the form and situation of these elements, considered in connection 

 with the evidence of other specimens presently to be noticed, can 

 leave no doubt that they are the homologues of the columella 

 (epipterygoid, Parker) found in Lacertilia, llhynchocephalia, Ano- 

 raodontia, Dinosauria\ and Chelonia. The bone on the right shows 

 a side view, while that on the left is seen either from behind or 

 before, and although both are fractured to a certain extent, their 

 boundaries are readily distinguishable. 



The right columella is 0"045 metre in total length, and is shown 

 of the natural size in fig. 1 " (p. 407). The upper end exhibits a tri- 

 angular expansion, which, before fracture, must have measured about 

 0*016 metre in greatest breadth ; and the long terminal upper border 

 thus produced has a gently arched contour. Immediately below the 

 expanded portion the bone becomes much constricted, having a 

 diameter of only 0*003 metre, and at the distance of 0019 metre 

 from the lower extremity it commences again to widen, but here in 

 an unsymmetrical manner. From the upper expansion downwards 

 the anterior edge is nearly straight, but at the point just mentioned 

 the hinder edge rapidly curves backwards, until the bone attains a 

 maximum breadth of 0*012 metre, when the border once more 

 descends almost vertically for some distance, and finally curves to the 

 front. The lower end, however, has evidently been much crushed, 

 like the remainder of the bone, and perhajis does not give an exact 

 idea of its original sliape. 



The left columella, presenting only an anterior (or hinder) view, 

 does not add any further details to the foregoing description ; but 

 this side of the fossil is of especial interest, since, as pointed out to 

 me by Mr. G. B. Howes, tliere appears to be some indication of a 

 downwardly-directed process of the parietal to meet the columella, 

 such as exists in the living Cyclodus^. There is no indication of 

 the fusion of the upper end of the bone with the parietal (or 

 ? "squamosal"), such as Prof. Cope describes (^. c. p. 204) in 

 the American form. 



In a skeleton of Ich(h>/osaurus from the collection of the late Prof. 

 Tennant (No. R 44 of the B.M. Register), the postorbital and 

 adjoining bones are so far removed and displaced as to permit an 

 admirable view of the lower end of the right coiumella, which is 

 uncrushed, and still in contact with the pterygoid immediately 

 behind the orbit. This is shown of the natural size in fig. 2. Its 

 front edge is almost vertical, but curves slightly forwards near the 

 lower termination, and there is a sharp anterior outer ridge along 

 the whole length of the bone. The expanded portion exhibits a 



' See O. C. Marsh, " Kestoration of Bronfosaums," Amer. Joura. Sci. (3) 

 vol. sxvi. p. 83 ; "On the Dipludooidre," ibid. (3) xxvii. p. 163; "The Order 

 Theropoda," torn. cif. p. 332. 



- The drawings have been made by Mr. W. H. Hill. 



^ T. H. Hiixlej', ' Anatomy of Vertebrated Animals,' p. ISO, fig. 69. 



