196 +] 
Cooper — Fossil Tardigrade 
47 
(regardless whether or not there are four, or but two, separate claw 
elements), eliminates the family Milnesiidae from further considera- 
tion. 
If the claws of each leg of Beorn leggi are two in number, and if 
each is in turn two-rayed (that is, the individual claw is a “dip- 
logriffe”), then it would be helpful to know whether basal lunules 
are present. But whether or not there are basal lunules, Haplornacro- 
biotus is eliminated as congeneric by the fact that the claws of each 
leg possess a total of 4 long rays in Beorn, and not 2 as in Haploma- 
crobiotus. Both the inequality of the rays, and the lack of rigorous 
symmetry of the claw rays about the median plane of the leg, and in 
lesser degree the sensible thickening of the dorsal cuticle in Beorn, 
set it apart from Macrobiotus. In these respects, and in its markedly 
subaverage size, Beorn leggi superficially calls to mind certain species 
of Hypsibius. The fossil form, however, differs sharply from the 
described species of both Hypsibius and Itaquascon (de Barros 1939) 
by the marked superiority in size of the major ramus of its inner 
(instead of outer) claws. Is Beorn, then, to be placed among the 
macrobiotids, more or less closely affined to Itaquascon and Hypsibius? 
The family Macrobiotidae encompasses forms with strongly devel- 
oped stylets and (aside from Itaquascon) a complicated internal 
buccal apparatus. Furthermore they possess gonoducts that enter the 
hindgut to create a “cloaca”. All of these features are regrettably 
unascertainable in the fossil in its present state of preparation. But 
inasmuch as the legs of Beorn appear to be telescopable and provided 
with a distal, anterior, cuticular scale (or flattened spine), and as the 
pattern of the claws in any case departs from those known in the 
genera of living macrobiotids, it seems prudent to set the fossil form 
aside in a separate family, Beornidae (n. fam .), with no implication 
as to the possible nature of stylets, buccal apparatus, genital and anal 
orifices, and so on. Though telescopable legs are a feature otherwise 
known only in certain Heterotardigrada, it seems an insufficient 
character to justify creation of a new order. The Beornidae are 
therefore viewed tentatively as a third family of the order Eutardi- 
grada. 
At present it seems that the current major classification of the 
Tardigrada is not likely to be an enduring one. Ther?nozodiu?n 
(Rahm 1937), for example, has a lateral cirrus but no clava, basal 
papillae on the legs, four peribuccal papillae, and pharyngeal skeletal 
elements, thus sharing cardinal features of Heterotardigrada and 
Eutardigrada alike. Beorn seems akin to eutardigrades, but possesses 
a telescopable leg. And within the Eutardigrada, Itaquascon bridges 
