174 



PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



yielding 8 species of Lower Ludlow starfishes and Westmoreland 

 4 Upper Ludlow. The Lower Ludlow Echinodermata therefore 

 number 11 genera and 19 species, the Upper Ludlow 6 genera and 

 7 species. None occur in Herefordshire, Scotland, or Ireland. 4 

 genera and 7 species (3 Crinoidea, 1 Cystidean, and 3 Asteroidea) 

 came from the Wenlock beds. In the Ludlow promontory and all 

 along the line that marks the junction of the Old Eed Sandstone 

 with the Upper Ludlow all Silurian life ceased. The slow elevation 

 of that region caused the Silurian Annuloid fauna to dwindle and 

 pass away almost entirely. No vestige of it again appeared in the 

 true Old Eed area anywhere ; and the want of evidence to show 

 what rocks may be below the Lower Devonian of the Devonshire 

 and Somersetshire areas leaves the question of stratigraphical or 

 zoological continuity one of doubt and in the region of the unknown. 

 Ireland or North Devon may yet solve the problem, for it is here 

 we should expect it. The new Ludlow genera were Echinocystites, 

 Palceasterina, and Tetragonis, none of which leaves any successors 

 behind, none being known either in the Devonian or Carboniferous 

 rocks. 



Annelida. — The Annelida are a singular group in the Ludlow 

 rocks ; 9 genera and 17 species have been obtained from the several 

 horizons (4), and their geographical distribution is wide also. 15 

 species occur in the Upper Ludlow; the characteristic Comulites 

 serpularius is the most abundant, occurring at all 4 horizons, and 

 in all localities except Shropshire and Ireland. The Lower Ludlow 

 has yielded Comulites serpularius, Serpulites dispar, S. longissimus, 

 Spirorhis Lewisii, and Tr achy derma squamosa. The Aymestry Lime- 

 stone contains 4 species, all of which are also in the Lower Ludlow. 



4 of the 17 species are also Wenlock. 3 species of ^Enonites and 

 3 species of Arabellites, belonging to the order Polyehseta, are 

 determined from jaw-remains by Mr. G. J. Hinde*; they are Upper 

 Ludlow, and help to swell the Annelide fauna. 3 species of the 

 order Tubicola occur in the Passage-beds. 9 species range through 

 South Wales, North Wales has 4, Westmoreland 6, Shropshire 5, 

 Worcestershire 7, Herefordshire 4, and Scotland 3 ; but none, so far 

 as I can ascertain, occur in Ireland. 



Cetjstacea. — The two great orders of the class Crustacea in the 

 Ludlow rocks are the Merostomata and the Phyllopoda. Of the 

 former we know 32 species — Eurypterus 10, Pterygotus 9, Himan- 

 topterus 1, Slimona 3, Stylonurus 3, and Hemiaspis 6. Of the 

 latter, through Ceratiocaris and Dietyocaris, we have 16 species ; and 

 there are possibly one Amphipod {Necrogammarus Sahueyi) and a 

 Poecilopod {Neolimulus falcatus, Woodw.). These 32 species of 

 Merostomata and Poecilopoda swell up the Crustacean fauna at the 

 expense of the Trilobita, which number only 10 genera and 20 

 species, 2 genera only of the 10 (Homalonotus and Phaeops) passing 

 to or occurring in the Devonian rocks. The Ostracoda number 



5 genera and only 13 species. The Crustacean remains termed Asta- 

 coderma by Dr. Harley, number 14 so-called species ; all are in the 



* Quart. Journ. Greol. Soc. vol. xxxvi. pp. 368-376. 



