44 CHELONIA CARETTA. 



short lateral angles, connected with the adjoining lateral plates; the fourth 

 vertebral is also hexagonal, but shorter, and with lateral angles more extended; 

 the fifth vertebral plate is pentagonal, slightly concave in front, with extensive 

 lateral margins and four articulating facets below. In the old animal all these 

 plates are nearly on a horizontal plane; the first being but very little curved 

 downwards in front, and the fifth as little behind. The lateral plates are five in 

 number, the first is smallest, with regularly triangular margins, and its basis 

 directed forwards and downwards; the second lateral is irregularly quadrilateral, 

 rounded below and in front; the third and fourth are pentagonal, with two short 

 borders above, meeting at an obtuse angle; the fifth lateral plate is irregularly 

 quadrilateral, broader below, or it has its posterior and inferior angle truncated 

 where it joins the eleventh marginal, which gives it a pentagonal form. Of the 

 twenty-five marginal plates, the intermediate or nuchal is short in the longitudinal 

 and more than three times as large in the transverse direction; it is small in the 

 middle, slightly concave behind, and much more so in front, and large at its 

 lateral extremities, each having two articulating surfaces, an upper smaller to join 

 with the first lateral, and a lower larger, to unite with the first marginal plate. 

 The anterior marginal is irregularly quadrilateral and arched outward; the second 

 is also quadrilateral, but concave in front; this and part of the fourth making a 

 border arched inwards over the anterior extremities; the third is irregularly 

 quadrilateral, smaller above, larger below; the remaining marginal plates to the 

 eleventh included, are quadrilateral, and make an entire border, sometimes waving, 

 between the tenth and eleventh; the twelfth or supra-caudal marginal plates are 

 sub-rhomboidal, and have a deep crescentic notch between them at their posterior 

 margin. 



The sternum is very full and rounded in front, smaller, but rounded behind. 

 The gular plates are large equilateral triangles, with their outer border rounded; 

 the brachials are regularly pentagonal, and so are the thoracic plates, but elon- 

 gated; the abdominals are broad and pentagonal; the femorals are also pentagonal, 

 but very irregularly so, having their posterior and external border concave; the 

 sub-caudal plates are triangular, with their outer borders rounded. There are 



