62 CALIFORNIA ACADEMY OF SCIENCES. 



XIX. Arges. Eyes ? Facial suture straight posteriori}-. Cheeks ? 

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

 pleurae are serrated. 



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

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

 minating at the posterior margin. Eyes generally unknown. 



XX. Cryptolithus Green (Trinucleus Murch.) Glabella clavate, divided 

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

 Eyes? ('. yranulalns Green, C caractaci Murch. 



XXI. Ampyx nasutus, rostratux Sars., ma77imillaius Sarti. Harpes Goldt. 

 differs from Trinucleus by the greater number of rings of the thorax. 



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

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

 out fins. 



Family VI. Oleni. 



XXI. Olenuti tensi?!?. 



XXIII. RemopletirideH colh'ii, loiujicnudufHs, hiteri-sphufer. 



XXI Y. Ceraurus Green. 



XXY. Agnostus Brong. (Battus Dalm.) -4. /lisijortnis Brong. 



Ueber die Trilobiten. 



In Neues Jarhbuch fiir Mineral., 1845, p. 18, 1 pi. 

 For list of genera, see preceding reference. 



On the morphology, classification, and distri- 



bution of the Trilobites. 



Scientific Memoirs, edited by Kichard Taylor, vol. 4, 1846, p. 2oS, 1 pi. 

 Translation of the preceding reference. 



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

 biter. 



In Mag. for Naturvidensk., Audeu Ewkkes. Christiana, vol. 1, 1833, p. 

 268, pi. 8. 



Trilobiter aseilus n. sp., T. elliptifrons n. sp., T. aphoerius n.sp., T. nemi- 

 hniarix n. sp., 7'. deiitaUix n. sp. 



Etheridge (Robert). Description of the Paheozoic and 

 Mesozoic fossils of Queensland. 



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

 Oriffithideii dubivif 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., Loudon, 4th series, vol. 14, 1874, p. 1. 



