354 Prof. T. R. Jones and Dr. H. B. Holl on the 



the majority in one species, were it not that in all probability 

 the several animals varied in their soft parts and limbs. 



B. Kloedeiii-suhtorosa is in the Smith Collection — no 17, 

 from Blue Holes, Riishal Canal, Walsall; no. ol, railway- 

 cutting, side of Severn, Ironbridge ; no. 32, Stoke-Saye, 

 Craven Arms ; no. 34, Woolhope (fig. 7). In the Vine Coll. 

 no. XLVi (fig. 6) and no. Lxvi, Tickwood Beds. 



(6) Beyrichia Kloedenij var. torosa, Jones. 



Beiirichia Kla'deni, var. torosa, Jones, Anu. & Mag. Nat. Hist. Sept. 

 1855, pi. vi. figs. 10 and 11, and fig. 12. ? 



Valves subquadrate, with two of the usual three lobes 

 broken up each in two smaller lobes. 



A specimen with a ^' big lobe," in Mr. Smith's collection 

 (slide no. 9), from Dudley Castle, has the gigot-lobe divided 

 into three lobules (figs. 1 a, 1 h)^ and thus closely imitates, if 

 it does not identify itself with, a variety of B. tuherculata. 

 See above, p. 349. 



IV. Lubes coalescing belotv. 



(7) Beyrichia Klosdeni, var. tuherculata, Salter. 

 (PI. XII. figs. Sa,b,9 a, b.) 



Proportions :— Fig. 8 : L. 35. H. 30.— Fig. 9 : L 22. 

 H. 12. Th. 9. 



B&irichia Klwde^ii, var. tuherculata, Salter, Geol. Mag. dec. ii. vol. viii. 

 1881, pp. u4o, 346 (for synonyms, &c.). 



W^e have remarked above (p. 351) that old individuals of 

 the granulate B. Khydeni have the roots of their lobes so 

 much thickened that they nearly coalesce, as in the variety 

 before us. The extremes seem at first sight to be quite 

 distinct, but sufficient gradations to connect them are met 

 with. 



1. In var. tuherculata the front and hind lobes are not at 

 all separated ; that is, they do not thin away and become 

 constricted below, but are broadly confluent in the ventral 

 region. The surface bears small tubercles, and in some cases 

 a minute interstitial pitting is also present (Smith Coll. 

 no. 18, Woolhope ; figs. 8 a, h). It sometimes has the exag- 

 gerated or hypertrophied lobe, and is then almost undistin- 

 guishable from an old big-lobed B. Kloedeni-gramdata. 



These specimens are coarsely granulated and at the dorsal 

 ends of the lobes bear one or more tubercles or small knobs. 



2. Mr. Vine's xxxviii (bed no. 25) similar, but not quite 

 so coarsely granulose. The internal cast shows a deeper 

 sulcus than is seen on the valve. 



