150 UPPER CRETACEOUS TELEOSTS 
bone, as long as deep, with a rounded posterior edge. The suboperculum is reduced 
in extent and the interoperculum is small. 
Hyoid arch and branchiostegal rays. Both the ceratohyal and the epihyal are 
visible below the dentary. Each is elongate and shallow, the ceratohyal attaching 
to a hypohyal anteriorly. The elongate median urohyal has an anterior articular 
region which is associated with the ventral region of the hypohyal. Sixteen bran- 
chiostegal rays are present, 8 of which articulate with the ceratohyal and 8 with the 
epihyal. The anteriormost 9 or Io branchiostegal rays are uniform in length and 
thickness, but the remainder gradually increase in length and girth. 
Paired fins and girdles. Due to the increase in size of the operculum the girdle has 
moved posteriorly and the occipital connection through the medium of the post- 
temporal is lengthened. Although the post-temporal is elongate it is of the 
normal forked nature with a more prominent flattened dorsal limb. The supra- 
cleithrum articulates with the postero-medial part of the post-temporal and from 
here it extends postero-ventrally to pass lateral to the upper part of the cleithrum. 
Two prominent postcleithra form a continuation of the supracleithrum. The 
dorsal postcleithrum is a large oval bone with a thickened anterior edge. The 
ventral postcleithrum is a thin splint of bone attached to the lowermost region of 
the upper. The lateral face of the cleithrum is expanded in a posterior direction 
above the fin insertion. The endoskeletal girdle is attached to the internal face of 
the cleithrum and the coracoid is visible ventrally as the more prominent of the two 
bones. 
The pectoral fin is greatly elongated and composed of approximately 12 rays. 
The first ray is the largest and articulates directly with the posterior edge of the 
scapula. The first ray appears to be unbranched but the remainder gradually 
decrease in length and are all branched. 
The pelvic bones are small slips of bone in the ventral body wall with posterior 
expanded articulatory regions. The pelvic fin consists of approximately g rays, the 
first of which is unbranched, the remainder branched. 
Vertebral column. The vertebral column is shown in the restoration, Text-figure 
68. It is composed of 35 vertebrae, of which 17 are caudal. The centra are slightly 
longer than they are deep and mesially constricted. The last few caudal vertebrae 
decrease in length somewhat. The anteriormost neural spines are longer and more 
delicate than those on the caudal region. The anterior neural arches are not rigidly 
attached to the corresponding centra, but the posterior arches are more intimately 
attached. Each neural arch does not extend along the entire dorsal surface of the 
centrum but is confined more to the anterior end, this is much more noticeable in the 
caudal region where the neural arches and spines are larger. Prezygapophyses and 
postzygapophyses are present on every vertebra, but again are more pronounced in 
the caudal region. Small transverse processes are present on the ventro-lateral 
parts of the precaudal centra, and have well developed, long flattened pleural ribs 
articulating with them. The haemal arches gradually extend into haemal spines, a 
complete spine being present by the third caudal vertebra. Pleural ribs still 
