NE 



ILLUSTRATIONS. aor 



Plates. 



I. Semionotus agassizii (W '. C. Redfield). Trias ; Sunderland, 



Massachusetts. Type of Newberry's so-called Ischypter. 

 us mars hi. X£ 



II. Semionotus agassizii (W. C. Redfield). Trias; Sunderland, 



Massachusetts. Head and anterior portion of trunk- 

 XT 



III. Semionotus fultus (Agassiz). Trias; Boonton, New Jersey. 



Figured specimen. X| 



IV. Semionotus micropterus (Newberry). Trias; Durham, Con- 



necticut. Xj 

 V. Semionotus elegans (Newberry). Trias; Boonton, New Jer- 

 sey. Figured specimen. X T 

 VI. Semionotus nilssoni Agassiz. Rhaetic ; Hoegenaes, Sweden. 

 Head portion of holotype, showing cranial plates and 

 dentition. X{ 

 VII. Ptycholepis mars hi Newberry. Trias ; Durham, Connecticut. 



XI 

 VIII. Ptycholepis marshi Newberry. Trias ; Durham, Connecticut. 

 Showing dorsal aspect of vertically compressed cranium. 



X 1 



T 



IX. Catopterus gracilis J. H. Redfield. Trias ; near Middletown, 

 Connecticut. Cotype. Xf 



X. Catopterus gracilis J. H. Redfield. Trias (Posterior shale) ; 

 Durham, Connecticut. Scales appearing whitish by 

 reason of mineral replacement. Xf 



XI. Catopterus gracilis J. H. Redfield. Trias ; Durham, Connect- 

 icut. x| 



