branchial. First ceratobranchial the shortest of the 

 ceratobranchial elements, which, except for the fifth, in- 

 crease slightly in size posteriorly in the series; possesses a 

 ventrally directed flange along most of its ventral sur- 

 face, this flange on the succeeding ceratobranchials 

 becoming progressively less developed until it is non- 

 existent on the fifth. First epibranchial with the dorsal 

 one-third of its length bifurcate into two projections; 

 the anterior projection articulating with the base of the 

 first pharyngobranchial, and the posterior projection ar- 

 ticulating with the second pharyngobranchial. First 

 pharyngobranchial (suspensory pharyngeal) a narrow 

 rod articulating ventrally with the anterior projection of 

 the first epibranchial and dorsally by fibrous tissue with 

 the area of articulation of the dorsolateral wing of the 

 parasphenoid with the anteroventral edge of the prootic. 



Second arch. — Basi-, hypo-, cerato-, epi-, and 

 pharyngobranchial elements present. Second basi- 

 branchial the largest of the three basibranchial elements; 

 articulates anteriorly with the first basibranchial, 

 anterolaterally with the first hypobranchials, posteriorly 

 with the third basibranchial, and posterolaterally with 

 the second hypobranchials. Second hypobranchial very 

 wide ventrally; articulates ventrally with the posterior 

 end of the second basibranchial and anterior end of the 

 third basibranchial, articulates dorsally with the second 

 ceratobranchial, which in turn articulates dorsally with 

 the somewhat laterally expanded second epibranchial. 

 The second pharyngobranchial is the first of the tooth 

 bearing pharyngobranchials, having seven or eight teeth, 

 set in sockets, in a single row on its ventral surface. The 

 teeth are of the same type as those of the jaws, although 

 slightly smaller and with sharper points. They are 

 replaced by new teeth developing in new sockets just an- 

 terior to the sockets of the old teeth, in the same manner 

 as in the replacement of the teeth in the jaws. 



Third arch. — Basi-, hypo-, cerato-, epi-, and 

 pharyngobranchial elements present. Third 

 basibranchial articulates anteriorly with the second 

 basibranchial, anterolaterally with the second hypo- 

 branchials, posterolaterally with the third hypo- 

 branchials, and posteriorly with the fourth cerato- 

 branchials. Third hypobranchial with an anteroventral 

 process which articulates by fibrous tissue with the 

 posterodorsal edge of the urohyal; at its posterodorsal 

 end it articulates medially with the posterior end of the 

 third basibranchial and laterally with the ventral end of 

 the third ceratobranchial. Third ceratobranchial ar- 

 ticulated dorsally with the third epibranchial, which in 

 turn articulates with the third pharyngobranchial, the 

 largest of the three tooth-bearing pharyngobranchial 

 elements. It possesses six to seven teeth in a row along its 

 anterior edge and about three more teeth irregularly 

 placed behind the anterior row. The teeth are similar to 

 those described for the second pharyngobranchial. The 

 third pharyngobranchial closely articulates by fibrous 

 tissue with the other two toothed pharyngobranchials 

 (second and fourth). 



Fourth arch. — Cerato-, epi-, and pharyngobranchial 

 elements. With the disappearance of the fourth basi- 

 branchial and fourth hypobranchial, the fourth cerato- 

 branchial articulates ventrally with the posterior end of 

 the third basibranchial. Fourth epibranchial an elongate 

 rod which articulates ventrally with the fourth cerato- 

 branchial and dorsally with the small fourth pharyngo- 

 branchial. The latter is the smallest of the toothed 

 pharyngobranchial elements, and closely articulates by 

 fibrous tissue with the third pharyngobranchial. It bears 

 five or six teeth in an anterior row and three or four more 

 teeth, irregularly placed, behind this anterior row. 



Fifth arch. — Ceratobranchial (lower pharyngeal) 

 element only. Fifth ceratobranchial wide anteroven- 

 trally but tapering to a short stout column dorsally. 

 Teeth more or less placed in three rows, with those of the 

 posterior row the largest; 7 to 10 teeth in the anterior 

 row, 7 to 9 teeth in the middle row, and 7 to 11 teeth in 

 the posterior row. The teeth are of the same type as those 

 of the pharyngobranchials. Ventrally the fifth cerato- 

 branchial articulates with the base of the fourth cerato- 

 branchial. 



PAIRED FIN GIRDLES. 



Pectoral Fin. 



Posttemporal. — A straight shaft of bone without 

 evidence of a forked condition, broadly overlying and 

 strongly interdigitated to the pterotic in the lower two- 

 thirds of its length and to the epiotic above. The rounded 

 ventral head of the posttemporal articulates by fibrous 

 tissue with the concave dorsal end of the supra- 

 clei thrum. 



Supracleithrum. — Located slightly obliquely 

 anterodorsally to posteroventrally in relation to the axis 

 of the body; articulates by fibrous tissue dorsally with 

 the ventral head of the posttemporal, and ventrally with 

 the cleithrum, which it broadly overlies. 



Cleithrum. —Laterally expanded along the ventral 

 two-thirds of its length; articulates by fibrous tissue dor- 

 solaterally with the overlying supracleithrum, while dor- 

 somedially it overlies the dorsal postcleithrum. Along the 

 middle of its posterior surface the cleithrum articulates 

 by fibrous tissue with the scapula and the rounded 

 anterodorsal portion of the coracoid. Ventromedially the 

 cleithrum articulates by tough fibrous tissue with its op- 

 posite member, while just above this region the anterior 

 end of the pelvis is firmly held between the cleithra. 



Postcleithra. — The postcleithra form a long 

 posteroventrally directed strut from the dorsomedial 

 region of the cleithrum along the abdominal wall 

 musculature to the region just above the middle of the 

 posterior half of the pelvis. The dorsal postcleithrum is 

 expanded into a thin plate dorsally and articulates by 



