472 SYDNEY E. JOHNSON 



The actinosts (ac.) are flat, rectangular bones, four in number, 

 to the outer edges of which most of the pectoral fin rays articu- 

 late. Between the superior actinost and the hypercoracoid is a 

 small foramen. A larger foramen occurs between the upper 

 two actinosts. All the others abut solidly (fig, 10). 



The pectoral rays {per.) are all segmented and they vary 

 greatly in length and thickness. Their number varies from four- 

 teen to seventeen, and, counting from above downward, the 

 seventh or eighth ray is the longest. Above and below this the 

 remaining rays decrease rapidly in length. The lowest ray is the 

 shortest, while the uppermost rays are more slender and deli- 

 cate. None of the rays are branched. The lower eight are free ; 

 the remaining are joined by a delicate membrane (figs. 4 and 

 10). 



The pelvic girdle {p.g.) is composed of two long flat bones 

 firtnly attached along the iniddle line. Their dorsal surfaces 

 are grooved near the lateral margins and on the ventral surfaces 

 there are ridges to correspond. At its lower end each bone sends 

 forward a triangular process terminating in a sharp point which 

 unites with its fellow of the opposite side (fig. 4). A wedge- 

 shaped depression between these tw^o processes is noticeable in 

 the unmutilated specimen. The pelvic girdle passes forward 

 and upward between the ventral blades of the clavicles. It is 

 firmly attached to the shoulder-girdle (figs. 4, 10). 



The ventral fin rays {v.f.) are three in number, segmented and 

 unbranched. The middle ray is one-fourth longer than the 

 outer, and nearly twice as long as the inner ray. There is a 

 very rudimentary spine at the base of each outer ray. The 

 rays are united by a delicate membrane and a single row of 

 papillae (scales) extends along the inner, ventral margin of each 

 ray (figs. 4 and 10). 



The posttemporal {pot.) is irregularly pyramidal in form and 

 bears on its inner edge a sharp, backward pointing spine. It 

 unites superiorly with the epiotic, anteriorly with the pterotic 

 and opisthotic for a short distance, and inferiorly with the exoc- 

 cipital. The supraclavicle articulates with the under surface of 

 the posterior spinous process (figs. 4, 5, and 7). 



