ENGLISH UPPER SILURIAN OSTRACODA. 141 



age, egg pockets, recesses for holding hepatic gland, 

 and to a parasitic origin like the swelling caused by 

 Bopyriis in the prawn. Beyrichia Maccoyiana has 

 got a striated flange somewhat like that possessed 

 by Beyrichia radiata. j^chmina cuspidata and ^. 

 bovina have curious long hollow spines situated near 

 the middle of the valve on the dorsal region, those 

 on ^'^. cuspidata being as long as the valves them- 

 selves. 



In 1887 Professor J. R. Jones published a list of 

 Silurian Ostracoda sent him by Professor G. Lind- 

 strom, of the State Museum, Stockholm. These 

 were from the Silurian rocks of Gothland, and were 

 referred to 33 species, 11 being identical to species 

 from the English Silurians. 



The conditions that prevailed during the deposition 

 of the Wenlock shales must have been much the 

 same as those that hold in the Firth of Clyde, two 

 or three miles off Ardrossan, at the present day. 

 With one haul of a small dredge we may bring up 

 as much fine mud as will give us on examination 30 

 or 40 species of Ostracoda, and as many of Forami- 

 nifera. So amongst the Silurian Wenlock shales we 

 may have in 10 or 12 lbs. weight of the decomposed 

 material as many Ostracoda, but of Foraminifera 

 we may only have one or two individuals, the more 

 highly organised Entomostraca of these early times 

 far outnumbering the more lowly Foraminifera. 

 But, on the other hand, the bivalve of the present 

 day takes the place of the more antique Brachiopod 

 which swarmed in the muddy bottoms of the 

 Silurian seas. 



Localities Examined. 



1. Walsal. — The shale from this locality, collected 

 at Blue Holes, beside the Rushall Canal, was of a 

 greenish-blue colour. It was not very fossiliferous. 



Ostracoda, 9 species. 



2. Dudley Tunnel. — The debris from this tunnel 

 has afforded a store-house from which many fine 



