ESPECIALLY MYCTOPHOIDS 145 
edge. Ventrally the supracleithrum attaches to the lateral face of the upper region 
of the cleithrum. 
The dorsal postcleithrum is similar in form to the supracleithrum, with a thickened 
anterior edge. The ornamentation of tubercles on the lateral face of the dorsal 
postcleithrum is from two distinct areas and the posterior edge of the bone is 
indented near its mid-point. (This seems to indicate that the dorsal postcleithrum 
represents the fusion of two separate elements.) The ventral postcleithrum is a 
small flattened rod of bone attached to the antero-ventral part of the dorsal post- 
cleithrum. 
The cleithrum is large and curved with its anterior edge inclined medially. 
Dorsally the cleithrum is narrow but more ventrally it expands where it follows the 
contour of the edge of the suboperculum. The anterior termination of the cleithrum 
is medial to the lowermost extremity of the preoperculum. The cleithrum is 
ornamented with radiating rows of tubercles. 
The endoskeletal girdle attaches to the internal face of the cleithrum and projects 
posteriorly and medially. The posterior edge of the scapula is thickened and has 
a distinct saddle-shaped facet for the anterior fin ray. The coracoid is larger and 
curves forwards ventrally to contact the anterior extremity of the cleithrum. A 
strengthening ridge from the scapulocoracoid junction passes forwards along the 
dorsal surface of the anterior extension of the coracoid. The coracoid projects 
posteriorly below the fin insertion. 
The pectoral fin has approximately 12 rays, the first ray being unbranched. All 
of the rays are stout basally and some are ornamented with bony tubercles. The 
fin is inserted low on the flank. 
Pelvic girdle and fin. Each pelvic bone is stout, flattened and with a prominent 
vertical strengthening ridge running along its length. The bones taper anteriorly 
to contact each other at the extremities. The posterior regions are thickened to 
form a prominent articulatory region for the fin rays and unite in the mid-line. 
The pelvic fin consists of approximately 11 rays and the first ray is unbranched. 
As in the pectoral fin the rays are stout, and certain of them are ornamented with 
ridges and tubercles. The rays are exceedingly elongate, the fin itself being much 
larger than the pectoral. The pelvic fins are in a sub-thoracic position, but the 
girdle does not contact either the cleithrum or the postcleithrum. 
Vertebral column. The vertebral column is shown in the restoration, Text-figure 
66. It has approximately 32 vertebrae, of which 16 are caudal. The individual 
centra are slightly longer than deep and are mesially constricted. The anterior 
neural arches are not intimately connected with the centra but the more posterior 
arches have a much closer connection, although the suture between the two structures 
is always clearly visible. In the precaudal region paired ventro-lateral transverse 
processes are found on each centrum and associated with these are long, thin, 
flattened pleural ribs. The first two caudal vertebrae bear haemal arches but only 
rudimentary haemal spines. More posteriorly the haemal spines are fully formed. 
Epineurals and epipleurals are present on the first 23 vertebrae. 
