332 Viscount (I'Archiac and M. de Verneuil 



England, Scandinavia, and the state of New York ; two are noticed in Bohemia 

 and one at Elbersreuth, in the middle system. Illanus occurs nearly under the same 

 condition : of this genus, one species, the /. crassicauda, Dalm., is met with in Scan- 

 dinavia, Ingria, Brittany, and the west of England ; two species are Devonian. At 

 present only five species of Ogygia are known, of which three are from the environs 

 of Angers, one from Llandeilo, and one from the banks of the Mohawk in the state 

 of New York. The genus Brontes is principally Devonian; the B. Jlabellifer, 

 Goldf., so diffused through the beds of the middle system of the west of England, 

 the Cotentin, Belgium, the Eifel, the banks of the Rhine, and found even on the 

 Asiatic exposure of the Ural, existed also when the upper Ludlow beds were de- 

 posited. The Oleni are occasionally met with in the first two systems. The Cryptq- 

 nimi are from Ingria and Esthonia*. The genera -Ba^^ws, Nilceus, Lychas and Am- 

 pyx belong principally to the Silurian beds of Scandinavia ; as the genera Otarion, 

 Ellipsocephalus and Conocephalus probably do to the less ancient beds of Bohemia f. 

 Lastly, the genera Isoletus, Eurypterus, Cryphaus, Dipleurus, Ceraurus, Triarthrus, 

 Nuttania, Brongniartia, and many others which contain only one or two species, 

 have yet been noticed only in North America. The Isoletes gigas appears to be 

 one of the most abundant Trilobites in that quarter of the globe +. 



In recapitulation, there are in the inferior strata 132 species of the family of 

 Trilobites, without including thirty-six North American species, of which the 

 greater part are probably found in beds belonging to the Silurian system ; there 

 are also thirty-two in the Devonian and twenty-four in the upper system : seven 

 only are common to the two first, while one alone pervades the three palseozoic 

 series. 



Among the other genera of the class Crustacea, we may mention a Limulus from 

 the coal-measures of Coalbrook Dale§ ; CytherincB, from the Silurian strata in the 

 island of Gottland 1| and the neighbourhood of Christiania, also from the Devonian 

 system ; and other minute genera, such as Cypris or Cytherina, Cypridina, Cyprella 

 and Cypridella, belonging to the Carboniferous system of Belgium, Scotland, and 

 some other countries^. 



Pisces.— li the Crustacea, highly elevated as they are in the scale of beings, 

 appear to have been among the first animals on the surface of the globe, such 

 was not the case with the class which succeeds them in organization. The 



* Eichwald, sur le Syst. Silur. de I'Esthonie, p. 77. 



t Verhandlungen Gesells. Vaterl. Mus. in Bohmen, Ap. 1 833, s. 49 et seq. 



I Second Report of the State of Ohio, 1838, p. 247, pi. 8. and 9. 



§ Dr. Buckland's Bridgewater Treatise, vol. ii. p. 77, PI. 46". fig. 3. 



II Hisinger, Lethaea Suecica, tab. 1. fig. 1, 2; for Scotland, see Dr. Hibbert's Memoir on the Fossils 

 of Burdie House, Trans. Roy. Soc. Edinb., vol. xiii. p. 169 et seq., 1836. 



% See de Koninck, sur les Crustaces Fossiles de Belgique. Mem. Acad. Roy. de Bruxelles, t, xiv. 



