EXTINCT BATEACHIA. 409 



APPENDIX 



Specimens of the following genera and species accompanied the ma- 

 terial described in the preceding pages, but are not included in the latter 

 on account of their position being, in the writer's opinion, among the 

 fishes. The interesting form Peplorhina is as yet but partially known. 



Peploehina, Cope. 



Proceedings Acad. Nat. Sci., Philad., 1873, p. 343. 



One of the specimens of Peplorhina displays the lower side of the 

 cranium, and on it two large jugular bones, one on each side, on the 

 inner side of the mandible. They are elongate, the posterior border 

 oblique, so as to present an apex on the inner side; the inner edge is 

 thin, the outer thickened ; the surface smooth, with a very obscure longi. 

 tudinal striation. Between their anterior extremities is a subround 

 disciform bone in the position of the basi- or glossohyal. The mandibular 

 rami extend round its anterior margin, and posteriorly nearly to the end 

 of the jugular. The symphysis is a curious interdigitation of three 

 fingers into as many notches, and the dentaries near them are marked 

 with symmetrical pores, which look like the exits of mucous ducts. 

 Three are on the superior and two on the inferior margin of the bone, 

 and a sixth is immediately between the upper and lower inner ones. 

 These pores correspond with the mucous ducts of the lateral line ob- 

 served in the scales of the type. The teeth are numerously placed in a 

 patch on the vomer, or at least the roof of the mouth, and are short, 

 conic, acute, and smooth. They are discoverable as far backwards as the 

 anterior end of the jugular plates. The large opercular bones are 

 smooth, and the head is covered above with nearly smooth, thin scuta. 

 The head is wide behind, and though contracted forwards, the muzzle is 

 broadly obtuse. Irregular masses, perhaps remains of cartilage, follow 

 the skull, in which a few ribs are scattered. 



The other specimen displays the smooth operculum, patch of vomerine 

 teeth, and several separated scuta of the surface of the cranium. These 

 have rounded angles, one or more convex sides, and very obscure radiat- 

 ing ridges. The body is covered with imbricated scales with cycloid free 

 margins, whose surface is marked with a tubercular sculpture. 



