64 J. MURRAY ON WATER-BEARS, OR TARDICRADA. 



Genus Diphascon Plate (Figs. 4 and 6) (25). 



General form like Macrobiotics. Pharynx with chitinous 

 thickenings. Teeth with bearers. Gullet elongate and flexible 

 between the attachment of the bearers and the pharynx, and in 

 some species at least strengthened by a spiral thickening like the 

 tracheae of insects (Richters). 



As the gullet in Macrobiotics is sometimes found elongate, 

 and as that constitutes the only original generic character of 

 Diphascon, the distinction between the two genera is but slight. 

 Professor Richters is also inclined to distrust this genus. 



The seven or eight species of Diphascon do, however, form a 

 natural group, even if the genus cannot be maintained. While 

 we find in Macrobiotics three or four different types of claws, all 

 the known species of Diphascon have claws of one type, that 

 found in Macrobiotics oberhdicseri. The two pairs of claws are 

 different (see Pig. 4). The larger pair consists of a very long 

 slender claw, laxly connected at the base with the middle of the 

 back of a shorter claw. The shorter pair consists of two nearly 

 equal claws, firmly joined at the base. The longer claws of each 

 pair have supplementary points, as in Macrobiotus. 



The eggs, so far as known, are smooth, and are laid in the 

 moulted skin. The pharynx may be shortly oval, as in Macrobiotus, 

 but in most species it is more elongate than in that genus. 



Eight species have been described, and seven of these are found 

 in Britain. 



Genus Milnesium Doyere (Figs. 14, 15) (2). 



This very well-marked genus contains only one undoubted 

 species. It is an animal peculiar in every part of its organisation. 

 A circlet of six palps surrounds the mouth, and a little further 

 back on the head are two similar palps. The skin is soft, like 

 Macrobiotus, and rather more distinctly segmented. The gullet 

 is very wide, and the teeth and bearers minute. The pharynx is 

 elongate and pyriform, and has none of the chitinous thickenings 

 found in Macrobiotus. The claws are very peculiar. There are 

 four on each foot. Two very slender, long, bristle-like claws 

 rise from terminal conical papillae. The lower claws are thicker, 

 and consist each of from one to three hooks. 



Two species have been founded on this last character — 



