Branchiostegal rays. —Six in number; first 

 branchiostegal ray a large flat oblique plate with a down- 

 turned lateral edge which becomes thickened anteriorly 

 to form the articular facet for contact with the vertical 

 groove on the ventromedial surface in about the middle 

 of the length of the ceratohyal; like that described for 

 Lagocephalus laevigatas, except that it is held in a much 

 more oblique position. Second branchiostegal slightly 

 laterally compressed; articulates at its knoblike anterior 

 end with a slight depression on the ventral surface of the 

 ceratohyal just behind the articular area of the first 

 branchiostegal; second branchiostegal ray about the 

 same length as, or slightly longer than, the third to sixth 

 rays. Third to sixth branchiostegal rays of about the 

 same length, but the sixth ray much narrower than the 

 others; all four rays held by fibrous tissue to the lateral 

 surface of the posteroventral region of the ceratohyal. 



Branchial Arches. — All the elements are cartilage 

 filled at their edges of articulation with the other ele- 

 ments in the series, and the articulations are usually 

 through cartilage and fibrous tissue. The branchial 

 arches are composed of three basibranchials, three pairs 

 of hypobranchials, five pairs of ceratobranchials, four 

 pairs of epibranchials, and three pairs of pharyngobran- 

 chials. Three gills are present; the fourth arch has no gill 

 and there is no slit between it and the lower pharyngeal. 



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

 pharyngobranchial elements present. First basi- 

 branchial wider posteriorly than anteriorly; displaced 

 forward so that it articulates posteriorly with the second 

 basibranchial and posterolaterally with the first hypo- 

 branchials. First hypobranchial a slender rod, slightly 

 wider dorsally than ventrally; the longest of the hypo- 

 branchial elements, which decrease in size posteriorly in 

 the series; articulates ventrally with the region of articu- 

 lation between the first and second basibranchials and 

 dorsally with the first ceratobranchial. First cerato- 

 branchial the shortest of the first four ceratobranchial 

 elements, which increase in length posteriorly in the 

 series, except for the fifth ceratobranchial which is 

 slightly shorter than the first ceratobranchial; first 

 ceratobranchial with a ventrally directed flange along 

 most of its ventral surface, while a similar flange is pres- 

 ent on the second and third ceratobranchials, as well as 

 on the fourth ceratobranchial in a much reduced state; a 

 large posterodorsally directed flange is present from the 

 dorsal edge of the ventral region of the first cerato- 

 branchial, and a similar, although slightly smaller, 

 flange is present on the second and third cerato- 

 branchials; articulates ventrally with the first hypo- 

 branchial and dorsally with the first epibranchial. First 

 epibranchial a slender rod, the shortest of the epibran- 

 chial elements; articulates dorsally with the first 

 pharyngobranchial. First pharyngobranchial a rounded 

 plate with a ventral shaftlike process for articulation 

 with the first epibranchial; bears about 15 to 25 small 

 sharply pointed teeth in a single but somewhat irregular 

 row along the edge of the rounded platelike region; the 



teeth smaller than those of the second and third pharyn- 

 gobranchials. The dorsal regions of the branchial arches 

 are held to the ventral surfaces of the parasphenoid and 

 prootics by fibrous tissue attaching to the dorsolatertd 

 surface of the epibranchials and phaiyngobranchials. 



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

 pharyngobranchial elements present. Second basi- 

 branchial somewhat constricted in the middle of its 

 length; articulates anteriorly with the first basi- 

 branchial, anterolaterally with the first hypobranchials, 

 posterolaterally with the second hypobranchials and pos- 

 teriorly with the third basibranchial. Second hypo- 

 branchial a short slender rod; articulates ventrally with 

 the posterolateral edge of the second basibranchial and 

 dorsally with the second ceratobranchial, which in turn 

 articulates dorsally with the second epibranchial. Second 

 epibranchial slender, rodlike; articulates dorsally with a 

 stubby projection on the ventral arm of the second 

 pharyngobranchial. Second pharyngobranchial the larg- 

 est of the pharyngobranchial elements; more or less L- 

 shaped, bearing a single row of about 10 to 15 sharply 

 pointed teeth along the edge of the wider of the two arms 

 of the L. The teeth are set in shallow sockets and are 

 curved slightly posteriorly. They are replaced by new 

 teeth developing in new sockets alongside the sockets of 

 the old teeth. The teeth of the second pharyngo- 

 branchial are of about the same size as those of the third. 

 The second pharyngobranchial is held by fibrous tissue 

 to the other two pharyngobranchials. 



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

 pharyngobranchial elements present. Third basi- 

 branchial large, rather squarish, articulates anteriorly 

 with the second basibranchial, posterolaterally with the 

 third hypobranchials and posteriorly with the fourth 

 ceratobranchials. Third hypobranchial a slender L- 

 shaped bone whose ventral arm articulates by fibrous 

 tissue with the ventral surface of the first basibranchial; 

 articulates posterodorsally with the posterolateral edge 

 of the third basibranchial and with the ventral edge of 

 the third ceratobranchial. Third ceratobranchial articu- 

 lated dorsally with the third epibranchial. Third 

 epibranchial a slender rod, with a stubby projection from 

 about the middle of its posterior edge which articulates 

 by fibrous tissue with a similar process from the fourth 

 epibranchial; articulates dorsally with the third 

 pharyngobranchial. Third pharyngobranchial like the 

 second pharyngobranchial, but much smaller and bear- 

 ing only about 7 to 10 small sharply pointed teeth in a 

 single row; articulates ventrally with the third and fourth 

 epibranchials. 



Fourth arch. — Cerato- and epibranchial elements 

 only. Fourth ceratobranchial a slender rod with only a 

 very low ventral flange along a short portion of its length; 

 articulates ventrally with the third basibranchial and 

 dorsally with the fourth epibranchial. Fourth epibran- 

 chial a slender rod with a low flange along its posterior 

 edge, and a stubby emargination from about the middle 



