A. LEITH ADAMS ON MALTESE LAND-TORTOISES. 



179 



The caudal vertebra (Plate V. fig. 1) has lost the posterior half 

 of the centrum, but is otherwise entire. The anterior zygapophyses 

 and concave centrum and transverse processes (a) are well preserved. 

 The last-named present rugged articular surfaces, indicating that the 

 costse were not ankylosed. There is a small neural crest. Un- 

 fortunately, in the few skeletons of the large recent tortoises in 

 collections, it is rare to find the caudal vertebrae ; so that I have had 

 no means of comparing the above with other allied forms. It 

 clearly, however, belonged to a land Chelonian of gigantic size. It 

 was discovered by me in conjunction with several teeth and bones 

 of the small form of Maltese fossil elephant (E. Falconeri). 



The length of the neck, so characteristic of T. elephantopus, and 

 probably of the other Galapagos tortoises, seems to have been also 

 a feature in T. robusta, if we may judge from the lengthened cen- 

 trum of the cervical here alluded to. 



Pectoral Arch. 



The very large coracoid process of the scapula (Plate V. figs. 2, 2 a) 

 is also referred to the Testudo robusta. The border of the distal 

 extremity is wanting, and there is a slight abrasion on the inner 

 border of the glenoid cavity ; otherwise it is entire, and in an ex- 

 cellent state of preservation, as, indeed, were the majority of the re- 

 mains from the Zebbug rock-cavity, owing to their investing matrix 

 having been a firm, tenacious blue marl. 



The articulating surface of the scapula (fig. 2 a, 5) is triangular ; 

 its maximum length is 40 millims, and greatest breadth 45 millims, 

 the glenoid cavity (c) being of about the same dimensions. The body 

 presents the usual contorted and trihedral configuration, expanding 

 at both the articular and distal extremities. 



The internal border is sharp, and the external rounded and uneven. 

 The superior surface of the body is also rounded, and thins out in- 

 ternally. The lower aspect (fig. 2) presents a triangular-shaped 

 depression (d) at the distal extremity, bounded by an cuter ridge (e) 

 and an inner ridge (/). The latter forms also the boundary to the 

 concavity (g) on the inner aspect of the bone. This excavation, 

 although not seemingly apparent in T. elephantopus, is present to a 

 small extent in the other Galapagos tortoise (T. vicina). Concerning 

 the relations with Mascarene tortoises I am unable to say any thing. 



The dimensions of fig. 2 as compared with the coracoids of Gala- 

 pagos tortoises are as follows : — 





T. elephan- 

 topus. 



T. vicina. 



T. robusta. 



Length of coracoid 



millim. 

 86 



20 



millim. 

 83 



33 



millim. 

 100 



38 



Least width of neck 





n2 



