STENEOSAUEUS. 107 



The coracoid (cor.) is likewise a bar of bone compressed from within outwards ; it 

 is much expanded at both ends. The lower (ventral) end is thin and its edge convex ; 

 it appears to have united with a cartilage. The anterior angle of the distal expansion 

 is truncated. The shaft of the bone is narrow, most markedly so in St. leedsi. At its 

 upper end it bends rather sharply inwards, passing into the dorsal upper expansion, 

 which is thus inclined at an obtuse angle to the ventral portion. The upper ex- 

 pansion is greatly thickened at its postero-external angle, where it bears the oblique 

 articular surface forming the lower half of the glenoid cavity (gl.f.) and terminates hi 

 the elongated roughened facet for union with the scapula. In front of this it is 

 produced forwards into a triangular plate terminating in a blunt angle ; this expansion 

 is perforated at its base by the coracoid foramen (_/'.), which opens below and in front 

 of the lower angle of the glenoid surface. The edge of this expanded poition was 

 probably fringed with cartilage in life. 



The fore limb (text-fig. 42), though much smaller than the hind limb, is not reduced 

 to nearly so great a degree as in the more strictly aquatic Metriorhynchus, but to a 

 somewhat greater extent than in the earlier (Liassic) Myslriosaurus and in the next 

 described genus Mycterosuchus (see p. 139). Moreover, although no well-preserved 

 fore foot is found in the collection, there seems to be no doubt that it was not modified 

 to form the paddle-like structure found in Metriorhynchus. 



The humerus (text-fig. 42, A-D), apart from its relatively smaller size, differs 

 considerably from the same bone in the recent Crocodiles. The upper end is much 

 expanded and is bent backwards to a considerable extent, so that its articular head (//). 

 looks much more backwards than is the case in the humerus of recent Crocodiles ; the 

 articular surface (text-fig. 42, C) is elongated, oval, strongly convex, especially from 

 above downwards. From the lower angle of the head a sharp ridge runs down on to 

 the shaft, while from the upper angle a slightly convex, thin, roughened border 

 extends to the deltoid crest (d.c), which is not very prominent; there is a shallow 

 bicipital fossa. The upper portion of the shaft is somewhat compressed in the same 

 direction as the proximal expansion, but the distal portion of the shaft, together with 

 the lower articular end, is slightly flattened almost at right angles to this, so that the 

 articular surface looks forwards instead of nearly downwards, as in recent Crocodiles. 

 The anterior face of the bone, above the condylar surface, is gently concave from side to 

 side, the concavity being bounded by a well-maiked ridge on the ulnar side. The 

 condyles (cd.) are not separated from one another by a distinct groove ; or rather it 

 would, perhaps, be more correct to say that only the radial condyle is developed ; this 

 is convex anter.orly and passes below into a nearly Mat surface occupying the distal end 

 of the bone. The posterior face of the distal articular region is raised into a median 

 ridge and marked by a series of longitudinal rugosities. 



The radius (text-fig. 42, E, F, r.) is a nearly straight rod of bone compressed 

 throughout its length, especially at its upper end, where it widens out to some extent. 



p2 



