EXPLANATION OF PLATE XIX. 
Clepsysaurxjs Pennsylvanicus, Lea. 
1. The proximal extremity of a llib, the head being broken off, as well as a small portion of the neck. 
The tubercle is entire. The anterior and posterior faces are represented at 1 and 1 a. 
2. A Vertebra imbeded in the rock. The posterior face is presented. The centrum has been carried 
off, leaving only a fragment. The spinous and oblique processes are nearly perfect, but somewhat 
bruised. The left transverse process is exposed. The canal is mutilated, and filled up with 
the matrix of hard Limestone. 
3. Fragment of the inferior portions of a Tooth, with its minute serratures imbedded in the rock. 
3 a. Two fragments of the superior portion of a Tooth, imbedded in the rock. 
3 b. The Tooth, reconstructed from the three fragments. 
3 c. Five transverse sections of the Tooth are correctly represented, and indicate the form of the faces 
of the fractured parts, passing from a gibbous to a circular transverse form. 
3 d. The Serratures of the Teeth, magnified about four diameters. 
