386 Proceedings of the 



plane. The hyoid arch is suspended by two ligaments, one 

 passing from the stylohyal to the epi-tynrpanic bone, and an- 

 other from the epihyal to the articular piece of the lower jaw. 

 The glossohyal bone is slender and linear, with a slight pro- 

 minence at the^ attachment of each of the four branchial 

 arches ; it was mere cartilage in the specimens examined. 

 The superior 'pharyngeal bones are circular, the inferior 

 elongated and triangular, and both pairs toothed like files. 



Anterior Extremity. — Only five bones, besides the fin rays, 

 enter into the skeleton of the anterior extremity. The supra- 

 scapula and scapula are replaced by one bone. This bone 

 fits into the notch between the projecting ex-occipital and mas- 

 toid bones, and stretching horizontally outwards, it expands 

 and bifurcates, forming a notch into which the coracoid bone 

 fits. From its under surface a long process shoots downwards 

 and inwards towards the basi-occipital bone, its course to which 

 is completed by a short ligament. The coracoid bone com- 

 pletes the arch of the shoulder girdle. One of its margins is 

 convex and directed forwards and outwards, and is some- 

 what flattened where it forms the posterior wall of the branchial 

 fissure. About one-third from its upper extremity the bone 

 becomes abruptly narrow, as if a piece had been cut out of the 

 concave margin which looks backwards and inwards. Its 

 breadth is supplemented by a bone which fits so closely on to 

 it as to seem a part of the same, and whose posterior margin 

 is continuous with the upper part of the posterior margin of 

 the coracoid. It lies on the outer surface of the coracoid bone, 

 and, widening as it descends, articulates broadly with its fellow 

 of the opposite side. The outer surface of the coracoid bone, 

 above the supplementary bone, is in contact with a cul-de-sac 

 of the peritoneal cavity, which contains a lobe of liver. This 

 circumstance, as well as the muscles directed forwards taking 

 origin from the inner surface of the shoulder girdle, shows 

 that the convex margin of the coracoid corresponds to that 

 which in most fishes looks backward and outwards. The sup- 

 plementary bone consists apparently of the radius and idna 

 combined. It presents two large processes toward its upper 

 end : one is vertical, and gives attachment to the outer part of 

 the pectoralis muscle ; the other is transverse, and perforated 



