Trof. n. G. SeeJey — On the Genus Ornithocheirm. 13 



In Glassia the spirals are connected as in Afrypa, but it materially 

 differs from this genus in the direction of its spirals. 



For more ample details readers are referred to my forthcoming 

 Silurian Monograph. 



(To be continued.) 



11. — On Evidence of two Ornithosaurians referable to the 

 Genus Or-vithoche/rus, from the Upper Gtreensand of Cam- 

 bridge, preserved in the Collection of W. Reed, Esq., F.G.S. 



By Professor H. G. Seeley, F.R.S., F.G.S. , etc. 



(PLATE I.) 



THE fragments of jaws of Ornithosaurs from the Cambridge 

 Greensaud show a greater variety in size, form, and proportion 

 than those from any other formation. The largest species were 

 apparently the most singular in the shape of the snout, but after 

 five-and-twenty years of collecting we still seem destined to know 

 them only from fragments which, though extraordinary and sugges- 

 tive, are tantalizing from their imperfect condition. It is impossible 

 to tell whether the head was short or long, or what proportion it 

 bore to the body, in the case of these isolated specimens, but some 

 of them, like the jaw-fragment which I am about to describe, show 

 a power of tooth and massiveness of bone which could only have 

 pertained to one of the most destructive and probably one of the 

 largest of these animals. 



This specimen, the anterior extremity of a jaw, was submitted to 

 me fourteen or fifteen j^ears ago, by the courtesy of W. Reed, Esq., 

 F.G.S., of York, and I then made the note on Ornithocheirus Eeedii 

 as well as the description of Ornithocheirus xyphorhynchus, a jaw of a 

 slender and altogether different type, which were included in 1870 

 in my book on the Ornithosauria. The specimens have again been 

 entrusted to me, for fuller description, but they still remain unique 

 examples of the species of which they are types. Unfortunately, 

 only the smallest portion of the palate is presei'ved in Ornitho- 

 cheirus Beedii, as though the specimen had lain snout downward 

 in the mud, and all the bone posterior to it had decayed. This 

 fragment of the palate is not more than a millimetre and a half 

 long in the median line where it is shortest, but it shows distinctly 

 a deep narrow median groove, hardly more than a millimetre 

 wide, which expands anteriorly and divides into two branches in 

 a V shape. This condition of a median groove in the jaw-bone 

 has hitherto been considered, and I believe correctly, to be distinc- 

 tive of the lower jaw, and I therefore propose, notwithstanding 

 the arrangement of teeth, which led me originally to regard it 

 as a pre-maxillary bone, now to interpret it as the anterior portion 

 of a dentary bone. I am led to this view also by the external form, 

 which indicates a rapid compression of the sides towards the lower 

 part of the jaw, and also by a remarkable oblique truncation of the 

 under side of the mandible, which is somewhat paralleled in the 

 Ornithocheirus machcerorhjnchus (Ornithosauria, pi. xii. fig. 1). The 



