376 MEMOIRS OF THE CARNEGIE MUSEUM. 



robust, and opercular apparatus complete, all more or less ganoid, mandibular 

 suspensorium vertical or inclined forwards, but gape of mouth wide; a distinct 

 azygous presymphysial bone present in the mandible; marginal teeth slender, 

 conical. Branchiostegal rays numerous. Vertebral centra annular or amphio- 

 coelous. Fins small, with broad, flattened rays, branched and articulated distally; 

 fulcra minute or absent. Scales rhombic, much deepened on the flank." (A. S. 

 Woodward, I. c, Pt. Ill, p. 415). 



This family, which perhaps may be regarded as ancestral to the modern gar- 

 pikes (Lepidosteidae) comprises two genera, which are distinguished by the following 

 differential characters : 



"Synopsis of Genera. 

 Rostrum much produced in advance of mandibular symphysis, and intercalary cheek-plate between the 



suborbitals and preoperculum; foremost scales of lateral line not deeper than those immediately 



beneath Aspidorhynchus. 



Rostrum scarcely if at all produced in advance of mandibular symphysis; suborbitals in contact with 



preoperculum; all scales of lateral line deeper than those immediately beneath Belonostomus." 



(A. S. Woodward, I. c, Pt. Ill, p. 415). 



Genus Belonostomus Agassiz. 

 " Snout very slender, scarcely if at all produced in front of the extremity of the 

 much-elongated presymphysial bone; cheek-plates robust, the postorbitals extend- 

 ing to the anterior border of the preoperculum; the conical teeth irregular in size, 

 largest on the hinder part of the premaxillse and the median line of the presymphysial 

 bone, obtuse on the splenial and reduced to a fine granulation on the inner face of 

 the ectopterygoid. Ossified vertebrae usually pierced by a remnant of the noto- 

 chord. Fin-rays distally bifurcating; fulcra wanting on paired fins, rare on median 

 fins. Pelvic fins situated near the middle of the trunk; dorsal and anal fins short- 

 based, triangular, remote and opposed; caudal fin symmetrically forked. Scales 

 robust, smooth or rugose; in three deepened series on the flank of the abdominal 

 region, and the series traversed by the lateral line the deepest; dorsal scales between 

 the flank scales and the median ridge in two series." (A. S. Woodward, I. c, Pt. 

 Ill, p. 498). 



19. Belonostomus muensteri Agassiz. (Plate LV, figs. 2 and 3). 

 1834. Aspidorhynchus munsteri L. Agassiz. 



Verhandl. Ges. vaterland. Mus. Bohmen, p. 70 (name only). 

 1837. Belonostomus munsteri L. Agassiz. 



Bericht Versamml. deutsch. Naturf., Jena, 1836, p. 127 (name only). 



