180 CALIFORNIA ACADEMY OF SCIENCES. 



In this contribution the initials of each aiithor designate the i^aragraphs 

 written by him. 



The following list is given of the Trilobite fauna of the Skiddaw slates: 

 Phacojys nicholsoni Salt. Cyhele ovata Eth. C'cdymene hrevicapitata ? 

 Remojjleurides s-p.l OZe?iws sp.? Trinucleus gibbsii ? Salt. Oyyrjia aelwyni 

 Salt. Ogygia s-p.^ BarrandiafalcataV.&cG. Niobe doveri 'Eth. Eurymeto- 

 pns n. g., E. camhrianus n. sp. P. & G., E. harrisonii P. & G. ^EgUna ? 

 rediviva'B&rx'., A. binodosa Salt., A. obtusicauda Hic'kii, A.? caliyinosa Salt. 

 Agnostus morei Salt. 



Prestwich (S.) On the geology of Coalbrook Dale. 



In Trans. Geol. Soc. London, vol. 5, 1840, ]). 413, map, 2 sections, 4 

 pis. 



The author mentions Asai^hus caudaius Briinn, A. tuberculato-caudatus 

 Mnrch., A. longicaudatus Murch. C'alytnene blumenbachii Brong. 



On plate 41 he illustrates Limuliis anthrax n. sp., L. rotundatus n. sp., 

 L. trilobitoides Buckland. Ajnis dubius n. sp. Anthrapcdtemon (Pakeo- 

 carabiis) dubiiis Salt. 



Dr. Woodward uses Ltmidiis anthrax and L. rotundxita for the tyjjes of 

 his new genus Prestivkhia. 



After a careful sttidy of the Limuii belonging to Prestwich's collection, 

 and also other specimens, this atithor remarks, that they are divisible into 

 two well-marked genera: 



(a) Those having movable thoracic segments and anchylosed abdomiua 

 ones; to be included in the genus Belinurus, namely Belinuriis trilobttokle><\ 

 Buckland, etc. 



(b) Those in which the thoracic and abdominal segments are not divided, 

 and which the former api^ear to be anchylosed. Prestwich'm anthrax and 

 P. rotundata. 



Quenstedt (F. A.) Beitrage zur Keiintniss der Tril- 

 obiten, mit besonderer. Riicksieht auf ihre bestimmte 

 Gliederzahl. 



In Archiv fitr Naturgesch. (Wiegmann), vol. 1, Berlin, 1837, p. 337. 



This work divides the Trilobites into two gi-oups: 



1. Trilobites with faceted eyes. 



•2. Trilobites with non-faceted eyes. 



The genera are classified according to the nitmber of segments in the 

 thorax, as follows: 



With 13 segments in the thorax: Trilobites blumenbachii Brong. fCaly- 

 mene callieephula Green, C. selenocephala Green?, C. platya Green. 



TrimeruA delpjhinocephalus Green. Calymene polytoma Dalm., C bella- 

 tula Dalm. Axaphus fischeri Eichw. These Trilobites form, loerhajjs, a 

 second section among the Trilobites with 13 segments. Their segments 

 are smooth and without grooves. 



