296 Prof. T. R. Jones on the 



tral Loldly rounded ; ends rounded and nearly equal ; like a 

 short Windsor or broad bean *. The valves have a crumpled 

 appearance at the mid-dorsal region, due to the presence of 

 three unequal tubercles (on each valve) and intervening fur- 

 rows, close together, and diverging more or less from the 

 middle of the hinge-line towards the depressed area within 

 the marginal rims. The tubercles are hollow inside, and 

 vary somewhat in the two valves and with individuals. The 

 free, curved edges of the valves are thick and generally some- 

 what raised ; and the left valve overlaps the right to some 

 extent ventrally. The hingement appears to be perfectly 

 simple. The surface of the valve is smooth, being destitute 

 of any ornament. 



Numerous individuals of this new genus, sometimes with 

 perfect valves closed together, but often imperfect, occur in 

 thin seams of limestone near Torquay, Devon (see Mr. Whid- 

 borne^'s Note at page 298). They constitute a considerable 

 portion of the rock, and become visible, like the other 

 organisms, only by the weathering of the limestone, whereby 

 it loses its blue colour and takes on tints of red and grey. 



There are two chief forms of this curious fossil, one semi- 

 circular and the other semielliptical in the ventral curve. 

 The latter is a variety, relatively larger and rarer than the 

 ther ; it has the three tubercles distinct (almost Beyrichian) 

 n the smaller or younger condition (fig. 8), and less so in 

 he larger individuals (tig. 10). Another variety (fig. 9) 

 has the tubercles still further reduced to two unequal 

 prominences. 



{ 



1. Kyamodes Whidbornet, gen. et sp. nov. 

 (PI. XI. figs. 1-7.) 



Figs. 1-5: Long l-j^^r mm., high 1^ mm., thick 1 mm. 

 Size -J Fig. 6: Long 1^ mm., high 1^- mm. 

 Fig. 7 : Long 2 mm., high 1^ mm. 



Semilunar in outline, being straight on the dorsal edge, 

 and otherwise almost semicircular, except that one end (ante- 

 rior) has a more rapid curve than the other, the postero- 

 dorsal thus becoming sharper than the front angle. The 

 edge view (fig. 4) is narrow-oval, modified ventrally by the 

 thickened edges of the valves, and dorsally showing in its 

 middle divergent furrows and intervening tubercles, some- 

 what like the undeveloped limbs of some embryo (fig. 5). 



* Hence the generic name Kyamodes, from Kva^iabris (for KvaiiofiST}s), 

 like a beau (Kvafios). 



