144 UPPER CRETACEOUS TELEOSTS 
Hyoid arch and branchiostegal rays. Separate dorsal and ventral hypohyals are 
attached to the anterior end of the shallow, elongate ceratohyal. The epihyal, like 
the ceratohyal, is long and shallow. Both ceratohyal and epihyal bear branchio- 
stegal rays ventrally. The number of branchiostegal rays is approximately ro and 
these become progressively stouter posteriorly. The urohyal is elongate and formed 
of two narrow lamellae of bone which contact each other along their dorsal edges. 
The urohyal extends back to the level of the articular facet of the mandible. 
pt d.pt 
v.pcl 
cor 
25mm 
Fic. 65. Phylactocephalus microlepis Davis. Pectoral girdle of the right side in lateral 
view. 
Pectoral girdle and fin. The pectoral girdle is shown in lateral view in Text-figure 
65. The post-temporal has a flattened, oval, dorsal limb articulating with the 
epiotic, and a shorter, strut-like ventral limb articulating lower down on the posterior 
face of the neurocranium. Posteriorly the post-temporal is expanded to provide a 
medial facet for the articulation of the supracleithrum. The dorsal surface of the 
upper limb of the post-temporal is ornamented with minute tubercles and the 
lateral line sensory canal passed through the main body of the bone. 
The supracleithrum is laterally flattened, with a thickened anterior edge. It is 
ornamented with minute tubercles arranged in rows following the long axis of the 
bone. The lateral line canal entered the supracleithrum midway down its posterior 
