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



Plate 



Carapace of Adoctjs punctatus Marsh, x £. — Drawn from type. 



(a) Bone Plates. — N, Nuchal ; 1-6, 9,-lst-6th, and true 9th Neuralia ; P, 

 Pygal ; Pm, Pygal Marginal ; PI, P2, P7, P8,-lst, 2d, 7th and 8th Pleuralia ; 

 M1-M5, Mll,-lst-5th and 11th Marginals. 



(b) Horn Shields. — N and 1, 1 st Vertebral ; 2 and 3, 2d Vertebral, etc. ; 

 CI, the 1st of the four Costals ; M1-M5, 1-5 Marginalia ; SC, supra caudal. 



( + ) Anterior, point at which the first and second ribs unite with 1st 

 Pleural. 



( 4- ) Posterior, point at which rib of tenth dorsal vertebra unites suturally 

 with the 8th Pleural, or else point of iliac support. 



