1108 



Oï the genus KJoedcnelht ri.üKii and Bassf^kh give the following 

 (iJMgnosis : 



"Carapace small, strongly convex, elongate, somewhat l)arrel-shape(K 

 the length nsnally less than 1.5 m.m., dorsal edge nearly straight, 

 ventral edge nsnally somewhat concave, ends approximately equal 

 in height but differing in outline, the antero-dorsal angle often rect- 

 angular and always more distinct than the post-dorsal. Valves 

 unequal, the right overlapping the left around the ends and the 

 ventral side. Of the lobation the constant features are two sharply 

 impressed vertical or slightly oblique furrows, separated by a narrow 

 lobe, in the posterior half. In the more simple forms these furrows 

 extend only about half across the valve. x\nterior half may be uni- 

 formly convex, but, as a rule, is more oi* less clearly bisected vertically 

 by a straight or cuj-ved furrow. When present, this anterior furiow 

 often produces an appearance suggesting the "loop" of a BoUla. 

 Surface generally smooth and polished and without ornamental 

 markings". 



Here the following remarks are to be made : first, that the way 

 in which the two valves are connected in Kloedenella lueroghipliica 

 Krause, as well as in Beyrichia tuberculata KlOden and Primltla 

 7'oJli BoNNEMA, proves that what Ulrich and Bassler called the 

 posterior end is to be looked upon as anterior. 



Secondly "dorsal edge nearly straight" ought to be replaced by 

 "Both vahes have a straight dorsal edge, the sharp dorsal edge of 

 the left valve lies in a furrow on the dorsal edge of the right valve. 

 On the left valve there is a process before the right dorsal edge, 

 which fits into a notch of the right valve." 



To "valves unequal" may l»e added that the right valve overlaps 

 the left along the hinge-line. This is at least also the case with 

 Kloedenella penn^yhanica as well as with Kloedenella hieroglypldca. 



The criteria of the genus Kloedenella are accordingly : 



Carapace elongate and small, the length usually less than 1.5 m.m., 

 posterior half very convex, dorsal edge nearly straight, ventral edge 

 usually somewhat concave, ends equal in height, anterior edge 

 uniformly curved and passing almost invisibly into dorsal edge, 

 forming a very obtuse angle with it; posterior edge less curved, 

 forming a nearly rectangular angle with the dorsal edge. Valves 

 unequal, the anterior half of the right valve has a notch in which 

 a process of the left valve lies; this latter is located before the straight 

 sharp hinge line, which is situated in the furrow on the straight 

 hinge line of the right valve. The right valve overlaps the left along 

 the hinge line. The sharp free edges of the right valve lie in a 



