Geological Society of London. 89 



were placed close together in sockets, 13 occurring in a space of 2| 

 inches. The general form of the vertebral centra indicates a convex 

 curve in the back and sacrum, and a concave curve in the neck and 

 tail, rendering it probable, in conjunction with the great develop- 

 ment of the sacrum, that the animal affected a semierect attitude. 

 The sacral vertebras, as preserved, are all separate. The scapula is 

 remarkably thick, with a strong spinous or acromioid process. The 

 femur shows distinctive Dinosaurian features, but presents a form 

 that has not previously been described. The vertebral centra 

 indicate a near affinity to Acanthopholis ; but no dermal armour has 

 been met with, and the caudal vertebrae present differences which 

 seem to justify its location in a distinct genus. 



IV. " On the Axial Skeleton of Eucercosaurus tanyspondylus, Seeley." 

 This genus is founded on an associated series of 19 vertebrae and a 

 neural arch from Trumpington. Four dorsal vertebras are preserved, 

 which considerably enlarge towards the sacral region, so that 

 probably the vertebral column was carried in a more than usually 

 erect position. The underside of the centrum in the early part of 

 the series has an angular or squeezed form ; but this appearance is 

 lost in the hinder centra. The sacral region is represented by 3 

 vertebra? ; there were probably, in all, 5 or 6. Twelve early caudal 

 vertebras are preserved ; these become unusually elongated and 

 prismatic posteriorly. The chevron bones were at first very large, 

 but are small when the articular face of the centrum has acquired 

 the hexagonal outline. The neural arch in the caudal region was 

 very depressed. This genus was considered to be closely related to 

 Acanthopholis, though the vertebras differed so greatly in form. 



V. " On the Skeleton of Syngonosaurus macrocercus, Seeley." This 

 genus is founded on a series of 19 vertebras, representing the neck, 

 back, sacrum, and tail. It shows affinities to several Dinosaurian 

 types, especially Eucercosaurus and Iguanodon. The early dorsal 

 vertebras are remarkably compressed, and the neural arches are 

 entirely united to the bodies of the vertebras throughout the series. 

 In the lower dorsal region the ridge on the visceral surface dis- 

 appears, and the centrum becomes deep. The visceral ridge re- 

 appears in the sacrum. The caudal vertebras are at first compressed, 

 and have the articular faces oblique and slightly procoslous ; the 

 chevron bones have a large single facet united by suture to the lower 

 half of the articulation. In these vertebras the visceral surface is 

 rounded and narrow. The proximal end of a humerus and distal 

 ends of both humeri were obtained ; they are of small size. Several 

 metatarsal bones and phalanges have also occurred, and are large in 

 proportion to the other remains. In doubtful association with these 

 bones were 11 pieces of dermal armour, closely resembling that of 

 Acanthopholis. 



VI. " On the Dorsal and Caudal Vertebras of Acanthopholis stereo- 

 cercus, Seeley." This species was founded on a small associated 

 series of vertebras, one of which is an imperfect cervical, 2 dorsal, 

 and 8 caudal. The species differs from A. horridus, Huxley, in the 

 form of the centrum, in the different character of the facets for the 



