OSTEOLOGY OF CAULARCHUS M/EANDRICUS (CIRARD). 299 



two stout ligaments are attached to it, one above and one below, 

 holding it firmly against the epiotic, but leaving it movable lat- 

 erally. 



The supraclavicle is a long simple bone. At its lower end is 

 a concavity which fits over a knob on the clavicle. 



The clavicle is slightly bent at an angle near its middle. 

 From its anterior edge a large lateral wing projects outward and 

 backward. A short distance above its middle on its anterior 

 edge is a tubercle of bone over which the cup-shaped end of the 

 supraclavicle is attached. 



The hypercoracoid is constricted at its middle opposite the 

 base of the upper actinost so that it appears as a fifth actinost. 1 

 This illusion is enhanced by the pectoral fin being joined to it 

 by two or three rays. It lies along the entire length of the upper 

 actinost, but is separated from it, except at each end, by an open 

 space similar to that between the actinosts. As the clavicle over- 

 laps the hypercoracoid to the edge of the hypercoracoid foramen 

 the foramen appears to be between these two bones. It is, how- 

 ever, through the middle of the hypercoracoid. 



The hypocoracoid is joined as usual to the clavicle and hyper- 

 coracoid but its lower end instead of returning to the lower end 

 of the clavicle, as usual in most fishes, projects backward along 

 the lower edge of the lowest actinost. This condition is evidently 

 brought about by the position of the pelvic girdle which is closely 

 attached along the inner lower edge of the clavicle. 



The actinosts are hour-glass-shaped, four in number, and sep- 

 arated from each other by open spaces. The coracoid elements 

 each support two actinosts. 



The postclavicle has lost its attachment with the clavicle and 

 lies free opposite the base of the pectoral fin just behind the 

 pelvic girdle. It is divided into two parts. The inferior portion 

 is curved around the outer and posterior portions of the ventral 

 disk, and the posterior fringe of the disk is attached to its edge. 

 The superior portion is very broad and from its posterior edge is 

 developed the peculiar fin-like flap seen externally on the fish 

 just behind the pectoral fin. In Gobiesox a flat process is devel- 



1 In the accompanying drawing this loses its deceptive appearance on account of 

 the exaggeration of the distinctness of the sutures. 



