TESTUDINID. 441 
At the junction between the epiplastron and the hyoplastron the greatest thickness is 30 mm. 
The ascending portion of the hyoplastron at the axilla has a considerable groove behind its 
free border and on the inner surface. Most of the hinder border of the entoplastron is at present 
missing, but it was evidently broad and rounded behind and pointed in front. The length in 
the midline was close to 110 mm. The greatest width is 160 mm. ‘The extent of the hyo- 
plastron in the midline is close to 115 mm. The hypoplastra occupy 130 mm. of the midline; 
the xiphiplastra, g7 mm. 
584. 588. 
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583. 590a. 
Fics. 583-590.—T estudo orthopygta. 
Plan of plastron, taken mostly from type. Slightly less than one-fifth the original. 
584. Section across the base of the epiplastral lip. Xt. 
585. Section across epiplastral lip, 25 mm. behind tip. X}. 
586. Longitudinal section of epiplastral lip. 4. 
587. Section of border of left hypoplastron, just behind inguinal notch. 
588. Pygal and left eleventh peripheral of type. 3. 
589. Section of eleventh peripheral near union with tenth. 4. 
590. Pelvis of type. il, ilium; isch, ischium; pub, pubis. 
The hinder lobe of the plastron (fig. 583) is short, and is provided with a notch behind, 
which has a width of 100 mm. and a depth of 24 mm. The lobe is flat below, concave above. 
At the inguinal notch (fig. 587) there is a wall 67 mm. high, with a perpendicular outer face, 
a rounded summit 16 mm. thick, and a steeply sloping inner face. Backward, the height of 
the wall rapidly diminishes, and the outer face soon changes to a slope less and less steep. 
At the apices of the lobe the height of the wall, above the lower surface of the bone, is only 30 
mm. Its width here is 45 mm. The middle portions of the lobe are about 12 mm. thick. The 
free borders of the lobe in the notch are acute. 
583. 
a, lower surface; , left side. 4. 
