60 CALIFORNIA ACADEMY OF SCIENCES. 



A. (Or.) caractaci Murch., A. fimbriatus Murch., A.radiatus Murch., 

 A. lloydii Murch. 



IX. Odontocephalus n. g. O.ovata n. sp. Calymene arachnoidea Goldf. 

 Cryphceus Green. 



The author figures Phacops rotundifrons, Conocephalus striattis, Odonto- 

 pleura ovata, Cryptolithus caractaci and Asaphus globiceps. 



Zur Naturgeschichte der Trilobiten. Pro- 



gramm zur offentlicheii Priifung, welche mit den Zog- 

 lingen der Realschule in Meiniiigen Donnerstag dem 

 28, und Freitag den. 29. Marz 1844 im grosseii Horsaale 

 der Anstalt abgehalten werden soil, etc. Meiniiigen, 

 1844, 1 pi. 



Pt. 1. Zur Morphologic der Trilobiten, pp. 4-13. 



Pt. 2. Ueber die Trilobitengattungen, pp. 13-18. 



Pt. 3. Ueber die Verbreitung der Trilobiten in den Gebirgsschichten, 

 pp. 18-28. 



The genera are arranged into 25 families in the following order: 



A Phacops in the restricted sense (Calymene Brong. in part). Con- 

 tractile. Pleurae rounded at the extremity, with an acutely-sharpened 

 anterior margin. Axis of pygidium furnished with 11 or fewer joints. 

 P. macrophthalmus Brong., protuberans Dalm., cryptophthalmus Emm. 

 (Calymene Icevis Mtinst.?), sclerops Dalm. (powisii Murch.), conophthalmus 

 Boeck., downingice Murch., procemus Emm., rotundifrons Emm. 



B Dalmania (Asaphus Brong. in part, Asaphus Goldf.) Not contractile. 

 Pleura at the anterior margin scarcely sharpened, frequently acute. Gln- 

 bella always clavate, distinctly lobed. Pygidium with more than 11, 

 sometimes as many as 22, joints to the axis, frequently elongated at the 

 extremity of the tail. Phacops caudatm Briinn., mucronatus Brong., 

 hausmanni Brong., odontocephalus Green., truncato-caudatus Port. 



II. Phillipsia Port. Facial suture extending to the posterior margin. 

 Glabella almost cylindrical. Thorax 9 to 10 jointed. 



(a) Nine- jointed species: Phacops kelli, jonesii, ornata. 



(b) Ten-jointed species: Asaphus dalmani Goldf. Calymene a-qua/is 

 v. Mey. 



Family II. Asaphi in the restricted sense. Contractile species. Pleuno 

 always sharpened at the anterior margin, generally obtuse at the extremity. 



III. Grimthides Port. Glabella gibbous, clavate. Thorax 9- jointed. 

 Pygidium furnished with 10 joints and upwards. G. globiceps, longisphixs 

 Port., obsoletus Phil. 



IV. Gerastos Goldf. (Proetus Stein.) Glabella truncate, cylindrical, 

 indistinctly lobed. Thorax 10-jointed. Tail less and indistinctly jointed. 

 G. concinnus Dalm. 



