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TRANSACTIONS OF THE AMERICAN PHILOSOPHICAL SOCIETY 



The cranium is strongly built. In the Chauliodontidae (Regan and Trewavas, 1929, p. 31) 

 the first vertebra is greatly enlarged and serves as a fulcrum for the head, which in turn 

 carries relatively short jaws with enormously long fangs. 



Qonostoma elongatum 



Fig. 53. Conostoma elongalum. Specimen cleared and stained by Miss Gloria Hollister for Dr. William Beebe. 



Parr (1927a, I930i) has traced the divergent evolution of three suborders as follows: 

 — (1) the Lepidophotodermi, including Stomias, which retains scales and has free premaxillse, 

 and possibly the Chauliodontids; (2) the Gymnophotodermi, including the Astronesthidse 

 and Melanostomiatidae (these have no scales and the premaxillse are fastened to the 

 maxillae, with highly differentiated luminous organs); (3) the Heterophotodermi, including 

 the Gonostomatidae and the Sternoptychidae. 



In conclusion, while some of the stomiatoid fishes approach certain of the Iniomi in the 

 development of long piercing teeth and of photophores, their retention in the Isospondyli 

 (in the restricted sense) rather than their inclusion in the Iniomi would seem to be justified 

 by the fact that they retain the primitive characters of a dentigerous maxilla, a supra- 

 maxilla, a mesocoracoid arch, typically abdominal ventrals and wholly soft-rayed fins. 

 Their connection with the Isospondyli seems also to be supported by the characters of 

 their otoliths, as Frost (1925, pp. 159, 160) notes that the otoliths of Go7iostoma denudatum 

 of the suborder Stomiatoidea, "resemble in their general lines those of Argentina, but are 

 more specialized in some respects. . . . The rostrum of this otolith is more produced 

 than in any other species of the order Isospondyli. . . ." 



Garstang (1932, p. 258) unites the stomiatoids with the Scopeloids under the name 

 Lampadephori, believing that the common possession of photophores indicates a com- 



