Mr. T. R. Jones on Beyrichise. 168 



XIV. — Notes on Palaozoic Bivalved Entomostraca. No. II. Some 

 British and Foreign Species of Beyrichia. By T. Rupeet 

 Jones, F.G.S. 



[Continued from p. 92.] 



[With a Plate.] 



In my former notice of Palaeozoic Bivalved Entomostraca ('An- 

 nals/ No. 92, p. 81, &c.) the Bei/richice of Sweden and Gothland 

 only were treated of; and I now propose to illustrate the British 

 species, as far as my materials will allow, as well as some foreign 

 species which I have had the opportunity of studying. I owe 

 much to Mr. Salter for his friendly advice and assistance in the 

 examination of these little fossils, and I have much pleasure in 

 acknowledging his kindness ; Mr. Morris also has kindly aided 

 me ; the Portuguese specimens have been lent to me by Mr. D. 

 Sharpe ; and to Sir R. Murchison I am indebted for permission 

 to use and to illustrate the specimens in the Museum of Prac- 

 tical Geology in Jermyn Street^ which form the largest portion 

 of the series. I ought here also to repeat my thanks to Prof. 

 Beyrich and Sir C. Lyell for the Scandinavian specimens above 

 mentioned ; for without them I could not have entered upon the 

 subject, and because a part of the materials of this notice also is 

 derived from that source. 



Like the Scandinavian species, the forms now described also 

 represent the three groups into which I divide the genus accord- 

 ing to the surface-divisions of the valves; — and they are de- 

 scribed in the same order. 



The figures in PI. VI. represent the objects magnified 4 dia- 

 meters, as in Plate V. 



Referring to my former communication for the generic cha- 

 racters, I proceed to the description of the several species. 



(JUGOS^.) 



1. Beyrichia complicata, Salter. PI. VI. figs. 1-5. 



Mem. Geol. Survey, 1848, vol. ii. part 1. p. 352. pi. 8. fig. 16 ; 

 Brit. Palseoz. Foss. Cambridge, 1851, part 2. fasc. 1. p. 136 

 (McCoy's descript.) pi. 1 E. fig. 3; ibid. 1852, fasc. 2. Appen- 

 dix A. p. ii. (Salterns descript.). 



Surface of valve depressed, deeply furrowed, and bearing three 

 sharply defined ridges, which are usually united by a connecting 

 ridge along the ventral margin. Anterior ridge largest, pear- 

 shaped ; middle ridge narrow, club-shaped : these two ridges, 

 somewhat curved and pointing obliquely downwards and back- 

 wards, are frequently less distantly separated than the middle 

 and posterior ridges are. The hindermost ridge is variously 



