406 CALIFORNIA ACADEMY OF SCIENCES. 34 



pital : near its middle it is connected with the posterior end 

 of the post-temporal, at which point it turns at a sharp 

 angle and runs to the clavicle. The second bone is much 

 larger, it is articulated to the basioccipital. Its posterior 

 edge is nearly straight for its whole length, but its an- 

 terior edge is produced and much swollen near its middle, 

 and joins the post-temporal over the first bone, then runs 

 to the upper end of the clavicle. 



The inner part of the clavicle and the coracoid are thin 

 and pierced by many holes, so that the bone in places is 

 little more than network. 



The hypercoracoid has a very large foramen; at its 

 posterior edge is a projection which supports a thin bone, 

 probably a dermal bone. 



The mesocoracoid is well developed. 



There are four actinosts; the first is long, but they 

 rapidly decrease in size to the fourth, which is short and 

 triangular. 



The first ray of the pectoral is large at the basal end, 

 and hollowed out; it works directly on the hypercoracoid. 



d. Branchial Apparatus. 



The branchial apparatus is peculiar in the adult, in 

 having gill-rakers somewhat resembling the filaments of 

 a feather, on both sides of each arch and on the basi- 

 branchial. They meet in a middle line between the arches 

 and unite forming a continuous lattice-work screen , through 

 which nothing but the very smallest bodies can pass. The 

 pharyngeals have no teeth, but have gill-rakers similar to 

 those on the arches; the}' are enclosed in sac -like pro- 

 jections on each side. 



This description is taken from the skeleton of a large 

 specimen 4 feet long. The gill -rakers are not united in 

 young specimens. 



r. Other Parts. 



