62 CALIFORNIA ACADEMY OF SCIENCES. 



XIX. Arges. Eyes ? Facial si^tiire straight posteriorly. Cheeks ? 

 Thorax 8-jointed. Pygidinm with an indistinct 4-jointed axis. All the 

 pleiirse are serrated. 



Family V. Trinuclei. Head with a broad even reticulate foveolate 

 margin, which is lengthened into horns posteriorly. Facial sntnre ter- 

 minating at the posterior margin. Eyes generally iinkuown. 



XX. Cryptolithns Green (TriniTclens Murch.) Glabella clavate, divided 

 into lobes at the sides. Thorax with 6 segments. Pygidinm articulated. 

 Eyes? C. gramtlaiitfi Green, C. caractaci Murch. 



XXI. Ampyx 7iasjttu>i, rostratus Sars., 7naw)iiltafiisiin,vs. Harpes Goldt. 

 differs from Trini;clei;s by the greater number of rings of the thorax. 



Section II. All the segments of the body at the posterior jiart of the 

 cephalic shield are homologous and movable, only the last joint is with- 

 out fins. 



Family VI. Oleni. 



XXI. Olcmin tesmiii. 



XXIII. Bemopleiirides rolh'ti, loiuj'irduddtna. hderi-sjiinifer. 



XXIV. Ceraurus Green. 



XXV. Agnostus Brong. (Battus Dalm.) A. /lis/jonnis Brong. 



Ueber die Trilobiteii . 



In Neues Jarhbuch ftir Mineral., 1845, p. IS, 1 pi. 

 For list of genera, see preceding reference. 



On the inorphology, classification, and distri- 



bution of the Trilobites. 



Scientific Memoirs, edited by Eichard Taylor, vol. 4, 184G, p. 2.5o, 1 pi. 

 Translation of the preceding reference. 



Esmark (H. M. T.) Om nogle nye Arter af Tiilo- 

 biter. 



In Mag. for Naturvidensk., Anden R;ekkes. Christiana, vol. 1, lSo:>, p. 

 2G8, pi. 8. 



Trilohlter as(;ilu,-i n. sp., T. ellipti/roiic n. sp., T. Kjihcrhis n. up., T. semi- 

 lunaris^ n. sp., T. deiitntux u. s]}. 



Etheridge (Robert). Description of the Paheozoic and 

 Mesozoic fossils of Queensland. 



In Quart. Jour. Geol. Soc. London, vol. 28, 1872, p. 317. 

 Grijfithides diihiiis n.sp., pi. 18, fig. 7. 



Observations on a few Graptolites from the 



Lower Silurian rocks of Victoria, Australia, with a fur 

 ther note on the structure of Ceratiocaris. 



In Annals Mag. Nat. Hist.. London, 4th series, vol. 14, 1874, p. 1. 



