494* 



palj:ontology of new-yobk. 



SUPPLEMENTARY NOTE ON THE GENUS PTERYGOTUS. 

 The monograph of Messrs. Huxley and Salter, referred to on page 417*, 

 furnishes the accompanying illustration of the Genus Pterygotcs ; being 

 a restored diagram of P. bilobus, of the natural size. 



The figures and letters, with the reference to the parts, and the no- 

 menclature employed, are copied from the explanations of the figure in 

 that monograph. 



a. Bye«. 



b. Anteonit. 

 b'. CheU. 



c. The endognatbs with 

 their palpa : their ba- 

 aal joints arc, for dis- 

 tinctness' sake, repre- 

 sented u if the; were 

 widely separated in 

 the middle line. 



d. e. The ectognaths, 

 with their palp*- 



/. The epistoma, or con- 

 joined epistoma and 

 labnun. 



g. The metastoma. 



1 - 13. Baccessire seg- 

 ments : 1, carapace; 

 2-12, segments of the 

 body; 13, telson. 



