2 BRITISH PALtEOZOIC PHYLLOCARIDA. 



TABLE OF THE KNOWN GENERA OP FOSSIL PHYLLOCARIDA. 



I.-CARAPACE, UNIVALVE. 



I. Flat or slightly convex Shield. 

 1. Neither sutured nor ridged along the back. Notched in front. 



A. Posterior border entire. 



Middle and Up-") , ^. . -^ ^^ . 



per SUurian.i ) Discmocans, H. Woodward. 1866. | Equ^j g^ieid . angular notch. (These are 



Triassic. 2. Aspidocaris, Eeuss. 1867. j Possibly the same.) 



Devonian. 3. ? Spafkiocaris, Clarke. 1882. Angular notch. - 



— 4. ?P7ioladocaris, 'Q.W. 1882. Sinuous notch. 



— 6, ? Lisgocaris, Clarke. 1882. Oblong notch. 



— 6. ? Mlipsocaris, H. "W. 1882. Eounded notch. 



B. Posterior border slightly notched. 



— 1. ? Cardiocaris, H. W. 1882. Front notch oblong. 



c. Posterior border deeply notched. 



Lower Silurian.i 1. ? Pterocaris, Barrande. 1882. Both notches angular. Test radiately marked. 

 Lower Silurian ^ 2. Bipterocaris, Clarke. 1883. Both notches angular. Test ridged along the 

 and Devonian. J middle. 



Lower Silurian. 3. ? Crescentilla, Barrande. 1872. Both notches angular. Possibly a sutured 



form. 



2. Ridged along the back. (Like Apus.) 



Devonian and ) 1. Dj^^rocom, Scouler. 1843. Eidged and sometimes prickly. -j ^ These are 



These shields differ in shape. 

 Some of them are pro- 

 bably the Aptychi of Oonia- 

 tites. 



Carboniferous. > {Argas, Scouler. 1835.) f S possibly the 



Carboniferous. 2. Rachura, Scudder. 1878. (Only telson known.) -' ^ same. 



3. Sutured along the back. Notched in front. 



„., . I 1. Aptychopsis, Barrande (and H. W.). 1872. Angular notch, 



per Silurian, j -^ .^ j- 



Lower Silurian. 2. Pelfocaris, Salter. 1863. Eounded notch. 



— 3. Pinnocaris, E. E. Jun. 1878. Slight notch. Striae concentric far back. 



II. Folded Shield, bent along the back (like Nesazia), so as to foem an ovek- 

 AROHiNG Carapace, oe a paie op attached Valves. 



Lingula-flags. 1. Hymenocaris, Salter. 1853. Smooth. 



Lower Silurian. 2. ? ' Cytheropsis testis,' Barrande. 1872. Not well known. 



Uppermost Devo- -v 



nian or Lowest > 3. Protocaris, Baily. 1872. Not well known. 



Carboniferous. J 



^ In the old or Murchisonian sense. 



