bluntly rounded than are the teeth of the upper pharyn- 

 geals. There are up to 15 teeth in the anterior series and 

 only slightly fewer on the average in the larger posterior 

 row, with 5 to 8 teeth in the middle row. Ventrally the 

 fifth ceratobranchial articulates with the base of the 

 fourth ceratobranchial. 



PAIRED FIN GIRDLES. 



Pectoral Fin. 



Posttemporal. — A straight sheift of bone without 

 evidence of a forked condition, broadly overlying and 

 strongly interdigitated to the pterotic in the lower half of 

 its length and to the epiotic above, and, to a much lesser 

 extent, with the posterodorsal part of the sphenotic. The 

 rounded ventral head of the posttemporal articulates by 

 fibrous tissue with the concave dorsal end of the supra- 

 cleithrum. 



Supracleithrum. — Located more or less vertically 

 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 over- 

 lies for its entire length. 



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 one-sixth or one-fifth of 

 the postcleithrum. Along the middle of its posterior sur- 

 face the cleithrum articulates by fibrous tissue with the 

 scapula and the anterodorsal region of the coracoid, 

 which it slightly overlies and mildly interdigitates with 

 in larger specimens. Ventromedially the cleithrum ar- 

 ticulates by tough fibrous tissue with its opposite mem- 

 ber, while just behind the top of this region the anterior 

 end of the pelvis is firmly attached to the rear edge of the 

 cleithra. 



Postcleithrum. — The postcleithrum forms a long 

 posteroventrally directed, sturdy, more or less flattened 

 shaft from the dorsomedial region of the cleithrum along 

 the abdominal wall musculature to the region over the 

 posterior third to one-half of the posterior half of the pel- 

 vis. The postcleithrum is a single piece without evidence, 

 even in small specimens, of being divided into an upper 

 and lower portion. The middle region of the postcleith- 

 rum is strengthened on the inner surface by a thick shaft. 



Coracoid. — Rounded dorsally, tapering ventrally to 

 a narrow shaft; produced posterodorsally into a prong 

 below the lowermost actinost; cartilage filled along its 

 dorsal edge and at the extreme anteroventral end; ar- 

 ticulates anterodorsally by fibrous tissue and slight inter- 

 digitation with the posterior edge of the cleithrum, which 

 slightly overlies it; articulates dorsally through cartilage 

 with the scapula and by fibrous tissue with the base of 

 the lowermost actinost. 



Scapula. — Completely encloses the scapular 

 foramen; concave and cartilage filled at its anterior and 

 ventral edges; articulates anteriorly by fibrous tissue 

 with the cleithrum which overlies its extreme anterior 

 region, while ventrally it articulates through cartilage 

 with the coracoid. Posteriorly the scapula articulates by 

 fibrous tissue with the following elements, in order from 

 dorsal to ventral; the first pectoral fin ray borne on a long 

 knoblike projection and just behind it the small first or 

 uppermost actinost followed by the second and third ac- 

 tinosts which articulate along the lower third of the pos- 

 terior edge of the scapula. 



Actinosts. — Four elements; cartilage filled at the 

 dorsal end and, to a lesser extent, at the ventral end; the 

 three uppermost actinosts articulating with the scapula, 

 the lower actinost being supported by the posterodorsal 

 edge of the coracoid; distally the actinosts support all of 

 the pectoral fin rays except for the first. The actinosts in- 

 crease in size from the first to the fourth. 



Fin rays. — Usually 13 or 14 fin rays; the first ray 

 very short, only about one-tenth the length of the second 

 ray, the medial half much larger than the lateral half and 

 articulated directly with the scapula rather than with the 

 actinosts as are the other fin rays; the first two rays and 

 the last or lowermost ray unbranched, the intervening 

 rays branched. The small first ray without cross-stria- 

 tions; all other rays with cross-striations. 



Pelvic Fin. 



Pelvis. — A sturdy shaft, the two halves either 

 variously fused or extensively interdigitated together so 

 that the impression is that of a solid bone like a raiboad 

 rail in cross section behind the level of the pelvic spine. A 

 single oblique crest on the side of the pelvis at the level of 

 the flange of the pelvic spine allowing for two and only 

 two positions of locking the erected spine. The shaft of 

 the pelvis tapering to a point posteriorly. Anterior to the 

 level of the pelvic spine, the anteroventral end of the pel- 

 vis bifurcates into a concave region for muscle attach- 

 ment, extending up along the anterior base of the antero- 

 dorsal shaft of the pelvis. The anterodorsal shaft of the 

 pelvis articulates by strong fibrous tissue just above the 

 region of close medial articulation of the two cleithra. 



Pelvic spine. — Large and strong; the medial end ar- 

 ticulating to the pelvis in much the same manner as 

 previously described for the triacanthodid Parahollardia 

 lineata. However, in the Triacanthodidae the side of the 

 pelvis at the level of the flange of the pelvic spine is 

 either smooth and thus allowing for a single position of 

 erection of the spine or it has numerous small grooves 

 allowing for numerous, continuous positions of erection 

 of the spine, rather than as in the Triacanthidae, ex- 

 emplified by Pseudotriacanthus strigilifer, in which 

 there is a single relatively large oblique crest allowing for 

 only two positions of erection. The rotation of the spine is 



