NATURAL SCIENCES OF PHILADELPHIA. 15 



TESTUDINATA. 



PUPPIGEKTJS PARVITECTA, Cope. 



Trans. Amer. Philos. Soc, XIV. 155 (C'lielone). P. parviscutum (lapsu 

 calami) 1. c. 235. 



Squankum. 



LEMBONAX POLEMICUS, Cope. 

 Trans. Arner. Philos. Soc, XIV. 168. 

 Farmingdale. 



LEMBONAX PROPYLAEUS, Cope, sp. nov. 



Established on an anterior portion of a carapace. This is very 

 peculiar in all respects, and throws much light on the character 

 of the genus. The anterior vertebral or nuchal bone is preserved 

 entire. It is recognized from its combination of a free concave 

 margin, with a basis of attachment of the first dorsal vertebra, 

 and from the first marginal bone on each side symmetrically 

 placed. The sutures thus exposed are very peculiar, and entirely 

 unlike those of any turtle known to me. It is a kind of com- 

 pound gomphosis, or mixture of the gomphosial and squamosal 

 types. The prominences are long, and penetrate deeply; they 

 are flat, and many grooved on both sides. The suture uniting 

 the nuchal and first costal consists of a median lamina from the 

 former, and two from the latter, fitting into grooves, but deeply 

 grooved, and divided on the edges. That uniting the first mar- 

 ginal is double squamosal, the former entering a groove of the 

 latter, which sends its inferior lamina far under the marginal. 



The nuchal is crescent shaped, the anterior or free margin 

 forming the a ncavity. The horns or external angles are much 

 more produced than is usual in turtles, extending on the inner 

 side of the marginals, and gradually tapering to a point. The 

 middle of the edges of the first marginal takes part in the con- 

 cavity of the front of the carapace. This concavity is thus more 

 extensive, both in respect to its depth and width, than in any 

 living member of the order, having but a slight representation in 

 some of them. Its edge is subacute in the middle and thickened 

 laterally. It is bordered on each side apparently by a prominent 

 angle for the edge of one (the best preserved) of the marginals 

 turns posteriorly, and is thinned out. 



The texture of the bone is closely spongy, with scarcely any 

 1872.] 



