ON THE LIXGULA-FLAGS OF SOUTH WALES. 



283 



Fossils of the ' Menevian group,' or Lower Lingula-flag. 



This list will surely he increased. But it may serve already to show the 

 near resemblance the group bears to other parts of the Lingula-flag or Upper 

 Cambrian series in some points, and the wide difference in others. ATI the 

 species are distinct. Many of the genera are only known here at present, 

 e. g. Paracloxides, Microdiscus, Anopolenus, Erinnys, Holocephalina, and the 

 peculiar sponge, Protospongia. The Cystidean may be different from others. 

 But we cannot yet prove this, though it seems likely. 



In beds higher up in North Wales Olenus is found. But of this more 

 hereafter. 



The " Menevian group" is distinguished by possessing the largest and 

 smallest of Trilobites — those with the most multiplied segments, and those 

 with the fewest. Paradoxides, Erinnys, and Olenus are the opposites in every 

 respect of Agnostns with 2, and Microdiscus with 4 segments to the body. 

 Indeed Erinnys (if it can be thoroughly separated from Harpides, which we 

 doubt) has nearly the greatest number of free segments known in the order, 

 more than Paradoxides ; but probably fewer than Harpes. 



* The length of the lines indicates the range of the species, long or short, as the case 

 may be. 



