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Report of the State Geologist. 



355 



These species were, at this date, mostly published without 

 illustration, but figures of them, and a few additional Devonian 

 species, were given in the Illustrations of Devonian Fossils, 

 in 1876. 



The following authors have published descriptions or notices 

 of the American Devonian Trilobites, and full reference to their 

 works will be found under the generic and specific synonymies : 



Walcott, 

 Whitfield, 

 Williams, H. S., 

 Williams, S. G., 

 Worthen. 



Barris, Conrad, Meek, 



Billings, Eaton, Nicholson, 



Brongniart, Emmons, Owen, 

 Burmeister, Green, Shumard, 

 Castelnau, Hall, Vanuxem, 

 Clarke, Kayser, Vogdes,* 



The other orders of the Crustacea have only more recently 

 attracted the attention of American writers. The Xiphosura have 

 been discussed by Williams and Packard ; the Eurypterida, by 

 Hall and Claypole ; the Phyllocarida, by Hall, Whitfield, Clarke, 

 Packard, Beecher, Woodward and Jones ; the Decapoda, by 

 Whitfield ; the Phyllopoda, by Clarke, Packard and Jones ; and 

 the Cirripedia, by Whitfield and Clarke. 



II. Classification. 

 In the discussions of the species, it has not seemed advisable 

 to accord a strict adherence to any given system of classification. 

 The Trilobites, which include the larger and, for the geological 

 student, the most important part of the work, stand first in order 

 of treatment ; the other orders of the subclass to which they 

 belong, being considered in the latter portion of the work. In 

 the introductory discussion of the genera the same order is 

 followed. 



The classification which has been adopted, with modifications, 

 for the purpose of the work, is the following : 



CLASS, CRUSTACEA. 



Subclass A : 

 Order I: 

 Family a : 

 Genus 1 : 

 Genus 2 : 



Family b : 

 Genus 3 : 



ENTOMOSTRACA. 

 Cirripedia. 

 Lepadidse. 

 Strobilepis. 

 Turrilepas. 



Balanidee. 



Protobalanus. 



Order II: 



Family a : 

 Genus 4 : 

 Genus 5 : 



Order III. 

 Family a: 

 Genus 6 : 



Phyllopoda. 



Limnadiadae. 



Estheria. 

 Schizodiscus. 



Trilobita. 



Calymenidse. 



Calymene. 



*It is understood that a "Bibliography of the Palaeozoic Crustacea." by Lieut. Vogdes 

 is ready for press at the present writing. 



