FAUNA OF THE GOSA.TJ FORMATION. 



071 



measurement is over a centimetre, and the thickness 6 millimetres. 

 There are no bones that I could refer to this species ; and when 

 they are discovered the teeth may prove to belong to an animal as 

 different from Hegalosaurus as is Lcelaps. 



Ornithomertjs gracilis, Seeley. 



The specimen figured by Biinzel, pi. vii. figs. 22, 23, and regarded 

 (p. 15) as the middle of the dorsal rib of a lizard, is the distal half of 

 the shaft of the femur of a remarkable new Dinosaurian. From the 

 circumstance that Biinzel has figured the external instead of the 

 internal aspect of the bone, it would have been difficult to make this 

 interpretation without examination of the specimen. The fragment 

 (PI. XXVIII. figs. 6, 7) is only 5| centim. long, has a nearly circular 

 shaftl3millim.in diameter at the proximal fracture, becoming a little 

 more compressed distally from above downwards and slightly more 

 expanded from side to side. The specimen shows no trace of the 

 distal articular end ; but distally the bone is a little flattened on the 

 inferior and posterior surface, and slightly compressed towards the 

 outer border. There is a distal curve in the bone, rather more 

 marked, perhaps, than in the crocodilian femur. Towards the proxi- 

 mal end of the fragment the transverse fracture passes through a 

 longitudinal muscular pit, margined below by an elevated muscular 

 ridge, which is prolonged further distally than the muscular pit, 

 and appears to have terminated in a free process, though the ex- 

 tremity of this is broken away. This is the internal trochanter of 

 the Dinosaurian femur (figs. 6, 7). What remains of the muscular 

 impression is about 12 millim. long and half a centimetre wide. 

 What remains of the sharp ridge bordering it is 17 millim. long. 

 I am not acquainted with any Dinosaur in which the femur has this 

 cylindrical bird-like form. The shaft is formed of dense bone with 

 a large medullary cavity about 7 millimetres in diameter (fig. 7), 

 and has, at first sight, rather the aspect of the bone of a bird than 

 of a Dinosaur. Though the fragment is so imperfect, it is so cha- 

 racteristic that I have ventured to refer it to a new genus. 



DoRATODON CARCHARIDENS (Biinzel). 



The sculpturing of the outer surface of the jaw, no less than its 

 general form, would seem to have weighed with Biinzel in referring 

 the specimen represented in his plate i. figs. 29-32 to the genus 

 Crocodilus. I find myself unable, however, to accept this generic 

 determination, partly because the teeth are such as indicate a dif- 

 ferent genus, and partly because I am led to refer the maxillary 

 bone represented in the same plate, figs. 3-5, to the same genus 

 and probably the same species as the lower jaw ; and this shows, 

 though the fragment is very imperfect, characters which are not 

 met with in the genus Crocodilus. But whether its affinities 

 are stronger with Crocodiles or with Dinosaurs is a matter 

 far from easy to determine. The lower jaw consists of slender 

 rami, having a length, as preserved, of about 13| centim. with- 



