LIFE ON THE EAKTH. 71 



Crustacea 7 genera. Agnostus Conocephalus 



Ellipsocephalus Hyme- 

 nocaris Olenus Para- 

 doxides Protichniites 

 11 species. 



Polyzoa One genus. Dictyonema 1 species. 



Brachiopoda 2 genera. Lingula Orthis. 3 species. 



The list is taken from a valuable catalogue of the 

 Lower Palaeozoic Fossils of the British Isles, in Mur- 

 chison's Siluria, Ed. n. 1859 \ The Crustacea belong 

 mostly to the great family of Trilobitidse. Norway 

 and North America yield each a series of the same 

 general character. A larger number of species has 

 been detected by M. Barrande in Bohemia, with the 

 same general aspect. Individuals of the Oleni, Lin- 

 guise and Oldhamise are abundant in certain layers, 

 but a large portion of the strata of this ' Primor- 

 dial ' Zone is devoid of all traces of life. 



Small as is this series of generic forms, we re- 

 cognize representatives of each of the three great 

 branches of the Invertebrata there are carnivorous 

 feeders as well as creatures nourished by cellular or 

 vegetable food and Fucoids are traced both in 

 Norway and Malvern, in beds below the Oleni. In 



1 Three species of Oleni found by myself in the black shales of 

 Malvern are included in this zone, though in the Catalogue re- 

 ferred to they are placed in the Caradoc formation. Murchison, 

 however, assigns these black shales to the early date here adopted 

 for them. Siluria, 45 et seq. 



