CERATIOCARIDiE 



FROM THE 



CHEMUNG AND WAVERLY GROUPS OF PENNSYLVANIA. 



By Chas. E. Beecher. 



The literature upon the subject 6i the paheozoic pliyllo- 

 pods is comparatively very meager and fragmentary. An 

 occasional discovery of a few specimens, as in the present 

 instance, has resulted in the publication of one or more new 

 forms, but nothing has led to a compilation and review of 

 the palaeozoic forms of the whole order. The trilobita 

 forming the bulk of palaeozoic Crustacea, and including such 

 varied forms and numerous species, have received much at- 

 tention from palaeontologists, so that a nearly complete mon- 

 ograph of this order is now possible ; while of the Ameri- 

 can ostracoda, merostomata, and phyllopoda, but little is 

 yet known which would furnisL materials for an exhaust- 

 ive monograph of the fossil species. 



In the present pai)er several new forms are j^resented and 

 considerable structural detail is hei-e first given for the genus 

 EcHiNocAKis, Wh/ffeJd, whicli it is hoped Avill add to our 

 knowledge of rhe zoological relations of this and allied 

 genera. 



Bibliographical History. 



1339. — The first ])aheozoic fossils of this order were found 

 in England and ])ublished by SirR. Murcliison. Professor 

 L. Agassiz considered tliem as fin -spines of iishes, and re- 



(I VVV.) 



