Am. Jour. Sci., Vol. XVII, 1904. 



Plate V. 



Carapace of Osteopygis Gibbi Wieland, x£.— Drawn from. type. 



N, Nuchal: 1-9, lst-9th Neuralia ; Pa, Pygal, anterior; Pp, Pygal, pos- 

 terior; Pm, Pygal Marginal; i-vni, lst-8th Pleuralia ; me, nuchal horn 

 shield ; sc, left supracaudal horn shield. — Bony plates in saw-tooth, and 

 horn shields in triple line border. 



