66 CARL L. HUBBS 



and Lyopomi, the rays are also all slender, usually numerous and 

 long, and frequently curved upward posteriori}^ about the free 

 margin of the opercular bones. The branchiostegals of the 

 Synentognathi (Belonidae, Scombresocidae, Hemirhamphidae, 

 Exocoetidae) are wholly similar to those of the typical Isospon- 

 dyli; they are rather numerous (ten in Euleptorhamphus) , but 

 not constant in number, flat, imbricate plates; the uppermost 

 skirting the lower margins of the opercula, and all with their 

 lower edges exposed. The characters of the branchiostegal rays 

 of the Synentognathi strongly confirm Regan's view that the 

 resemblance between these fishes and the Percesoces is purelj^ 

 fictitious : the group should be placed among the typical soft-rayed 

 fishes. In the Haplomi (Esox, Umbra, and Dallia), but not in 

 the poecilioid fishes which have been confused with them, the 

 branchiostegals are like those of the Isospondyli. In the Iniomi 

 (the Synodont fishes and their allies) the branchiostegals vary 

 greatly in number (from six to twenty, four to eight attached to 

 the suture between ceratohyal and epihyal, two to twelve below 

 the suture) ; in Plagyodus the uppermost ray, as in the Isospondyli, 

 is not wholly concealed, but in most of the genera several of the 

 upper rays are covered by the opercula; when the rays are numer- 

 ous several of the upper ones are closely approximated basally. 



The group of the ribbon fishes (Taeniosomi) has been accorded 

 very different positions among fishes, the current tendency being 

 to place it much lower in the series than formerly, a disposition 

 of the group which is doubtfully confirmed by the arrangement 

 of the branchiostegal rays. In Regalecus, according to Parker's 

 figure ('86), there are six slender, saber-shaped branchiostegals, 

 all attached to the outer face of the hyoid arch near its lower 

 margin; the uppermost, the only one attached to the epihyal, 

 curving around the lower margin of the interoperculum. In the 

 still more extremely aberrant genus Stylephorus, as described by 

 Starks ('08), the five rays are inclined upward from their origin 

 near the upper edge of the ceratohyal, as in no other known fish. 

 In Trachypterus arcticus, as described by Meek ('90), the branchi- 

 ostegal rays differ to no considerable degree from those of Rega- 

 lecus. As in that genus, they are six in number; the uppermost 



