No. 379.] DEVONIAN PTYCTODONTIDZ. 477 
The largest complete dental plate belonging to this species 
that the writer has seen is that shown -in Fig. 15; it is about 
Fics, 1-17. — Ptyctodus calceolus, N. and W. wha 18-27. — bate pega SP nov. Figs. 28-30. — 
P. molaris, Eastman. Figs. 3 — P. panderi, sp. x$ 
7 cm. in length and 1.5 cm. in maximum width. The tritoral 
area measures 3 X .8 cm., and the anterior cutting edge is 
about two-thirds as long as the tritor. The specimen shown 
in Fig. 16 is 5.5 cm. long; that figured in the preliminary 
