PalceozoiG Bivalved Entomostraca. 297 



The end view is roughly cuneiform, lumpy above, and notclied 

 below (fig. 3). 



On the right valve (fig. 1) three medial tubercles are 

 defined near the back and close together. One in front is 

 curved ; the middle one is low down and weak ; and the 

 hinder tubercle rises a little above the dorsal line, and the 

 valve is gently swollen behind it. In the opposite valve 

 (fig. 2) the anterior has coalesced with the middle tubercle, 

 and protrudes beyond the dorsal line, while the hinder 

 tubercle does not rise high up and has a slight subsidiary 

 ridge behind it. 



In figs. 6 and 7 the interiors of two left valves show 

 modifications of the hollows which correspond to external 

 elevations. 



1*. Kyamodes Whidhornei, var. elliptica^ nov. 

 (PI. XI. figs. 8 and 10, a, h.) 



a- fFig. 8: Long \.\ mm.^ less than ^ mm. high, 

 ^ize ^pjg.^ ^Q. L^^^^ 21 mm., H mm. high. 



With greater length, less height, and less convexity, the 

 adult form of this variety differs from the type described 

 above. The tubercles are not so strongly pronounced, the 

 two chief knobs being equal, not very prominent, and more 

 widely separate than in figs. 1 and 2. The middle tubercle 

 is much reduced, though visible on the anterior side of the 

 broad sulcus. 



In the smaller (probably younger) form, fig. 8, all three 

 tubercles are prominent, being defined by two intermediate 

 sulci and two curved furrows within and parallel with the 

 raised terminal margins of the valve. A Beyricliian alliance 

 of the genus is indicated by the distinctness of the lobes, the 

 widtli of the intervening depressions, and the greater relative 

 width of the posterior lobe, with the faint subdivisions of its 

 surface. The essential characters, however, are the same as 

 in fig. 10, and even there they are not specifically distinct 

 from those of the other forms (figs. 1-7) which have departed 

 so far from' the Beyrichian type. 



1**. Kyamodes Whidbornei, var. obsolescense nov. 

 (PI. XL fig. 9.) 



Size: Long 2 mm., high Ij mm. 



Here the sulcus is not so strong as in either of the other 

 forms J the anterior and middle tubercles are represented 



