Mr. T. R. Jones on Beyrichise. 173 



Silurian Entomostraca of Bohemia (now in the British Museum) 

 comprises several forms closely allied to this group. 



9. Beyrichia bicoi'nis, nov. sp. PI. VI. fig. 23. 



Car apace- valves flattened ; impressed with a distinct, short, 

 subcentral, dorsal pit-like furrow; a small semicylindrical tu- 

 bercle rises up on either side of the furrow. Marginal rim well 

 developed, sloping, and crested by a narrow continuous ridge. 

 The carapace- valves, in one or two rare well-preserved specimens, 

 are smooth ; but in various stages of dissolution the surface puts 

 on a deceptive pitted, reticulated, or carious aspect. 



The well-defined outline, raised border, and bi-tubercled sur- 

 face, with its deep subcentral notch, sufficiently characterize this 

 interesting little species. It is from the Harnage rock before 

 mentioned. (Mus. Pract. Geol.) 



10. Beyrichia seminulum, nov. sp. PI. VI. fig. 24. 



Carapace-valves convex, almost symmetrically semicircular ; 

 coarsely punctate ; impressed with an almost central dorsal fur- 

 row, extending across one-third of the width of the valve. Mar- 

 ginal rim distinct, uniform. 



I met with this neat little species in the Wenlock schists of 

 the Town Hill, Montgomery, as casts and impressions, in com- 

 pany with casts of B, Kloedeni. 



11. Beyrichia simplex j Jones. PI. VI. fig. 25. 

 Quart. Journ. Geol. Soc. 1853, vol. ix. p. 161 pi. 7. fig. 7. 



Carapace-valves convex, smooth, somewhat ovate; posterior 

 half of the valve much broader than the anterior ; ventral border 

 rounded ; anterior and posterior borders obtusely angular ; dorsal 

 border somewhat angular, formed partly of the straight hinge- 

 line (which is about half the length of the valve), and partly of 

 the obliquely rounded upper margins of the two extremities. 

 Dorsal furrow slight, subcentral, towards the anterior extremity. 

 Marginal rim indistinct. 



This species was established on numerous specimens, constant 

 in form and character, accompanying B. Bussacensis in the 

 Lower Silurian schists of Serra de Bussaco and Serra de Mucela, 

 near Coimbra, Portugal. 



/odB Bh simplex ? var. ? PI. VI. figs. 26, 27. 



Figs. 26" and 27 represent small individuals, which, with 

 )ther similar but somewhat variable forms, occur in numbers in 



