360 Prof. T. E. Jones and Dr. 11. B. Holl on the 



slightly convex. The ends are unequally rounded. The 

 valves all bear a raised ridge just within and concentric with 

 the ventral and terminal margins ; also three narrow trans- 

 verse lobes. These freely coalesce below, and, though some- 

 what variable, yet usually show that one (posterior), which 

 forms a loop at its upper portion (being there either impressed 

 with an oval pit, or formed of two short ridges meeting at 

 top), curves boldly forward below, and makes one with the 

 usually straight middle lobe ; whilst another (anterior) ridge- 

 like lobe goes off from (or joins) the root of the others with a 

 variable curve, or even at an angle. The depressed spaces, 

 or sulci, between the lobes, and between them and the strong 

 marginal rim, are deep and broad. The surface of the valves 

 is obscurely pitted. If the loop-like depression on the gigot 

 were open at the top, we should have a four-lobed Beyrichia j 

 but in some individuals the anterior and middle lobes keep toge- 

 ther in either an oblique or a curved position, and even nearly 

 coalesce at the top (in the antero-dorsal region), as if, intend- 

 ing to form a loop, they would imitate that of the other lobe, 

 and thus make a single, curved, narrow, ridge-like lobe, having 

 a loop (or oval depression) at each end. 



The form is rather rare and is new to us ; we call it 

 lacunata. Barrande's B. hohemica (Syst. Sil. B. vol. i. Suppl. 

 p. 498, pi. xxvi. fig. 13, and pi. xxxiv. figs. 18-22) and 

 M'Coy's figures of B. comjMcata (Pal. Foss. Cambr. 1851, 

 p. 136, pi. i. E, fig. 3) approach in character to this species. 



Smith Coil, no, 16. Eailway-cutting, Severn, L'onbridge. 



65. Woolhope. 

 Vine Coll. no. XLV. Tickwood Beds, uos. 25 and 25*. 



II. BoLLiA, gen. nov. 



In these Beyrichian Entomostraca the valves bear two lobes 

 meeting below with a thin curved isthmus. They have also 

 a marginal ridge, sometimes unequally divided ventraljy. 

 By the lessening of the lobes and the increase of the marginal 

 rim some forms seem to show a passage into Kirhhya. The 

 simple horseshoe swelling on the valve differs so much from 

 the three-lohed and the •plurijugale Beyrichue and from the 

 corrugate form or Kloedeniaj that we propose to give this a 

 generic standing as BOLLIA, in honour of the late Dr. Ernst 

 Boll, of Neubrandenburg (sec above, p. 338). 



