ECIIIXOCAKIS. PPP. 9 



size, less conspicuous and differently located nodes, and in 

 the more simple character of the ornamentation. 



This well-marked species occurs in the shales of the Ham- 

 ilton group at several localities in the central portion of the 

 State of New York. It is here introduced for the sake of 

 comparison, and for a better elucidation of the characters 

 of the following species. I am indebted to Professor James 

 Hall, for the permission to examine and figure specimens 

 of this species, belonging to the New York State Museum, at 

 Albany. These collections furnish conclusive evidence of 

 the identity of the abdomen and telson, referred to Ceratio- 

 caris armatus, with the carapace described as Ceratiocaris \ 

 pinictatus. 



The specimen Fig. 16, Plate I, is the only one yet ob- 

 served in this genus showing the mandibles and their posi- 

 tion. In 1865 Professor Henry Woodward, of the British 

 Musetim, described and figured a specimen of Ceratiocaris 

 papllio which preserved the mandibles and showed the po- 

 sition which they occupy in the carapace. These two ex- 

 amples add materially to our knowledge of the characters 

 of this group, and with the nearly entire specimens de- 

 scribed in this and in the succeeding species, furnish us 

 with material for a comparison with their recent ally — 

 Nehalia. 



Some of the specimens are covered with numerous exam- 

 ples of a small species of Crania^ which from the perfect 

 preservation of the EcJi i nocar is were probably attached dur- 

 ing the life of the crustacean. The shales carrying these 

 remains are highly charged with other fossils, among which 

 are fragments of fishes, Bei/richia^ Lepcrdilia, Phacops^ 

 Ilomalonotus^ OrtJcoceras^ Nautihcs^ Loxonema, Pleuro- 

 toviaria, Bellerophon, Platyostoma^ numerous species and 

 genera of lamellibranchiata, with a few species of brachio- 

 pods and bryozoaris. 



Associated with numerous specimens of E. pmictala are 

 frequently found mandil)les or jaws of the form I'epresented 

 in Figs. 9-11 of Plate 11. These are evidently of crustacean 

 origin and although somewhat similar in form to the mandi- 

 bles undoubtedly belongini; to E. punctata, they probably 



