184 J. MURRAY ON WATER-BEARS, OR TARDIGRADA. 



are slender and bear four equal and similar curved claws, which 

 are not elevated on " toes " as in Halechiniscus and Batillipes, but 

 are connected by a slight web at their bases. A moss-dweller. 



While nearest to Echiniscus, with which it would be united, 

 despite its other slight peculiarities, were it not for the un- 

 armoured body, it shows affinities with several other genera. 

 The soft body and the possession of bearers connect it with 

 Macrohiotus. The elevation of seta a and its elongated palp on 

 a papilla make an approximation to Halechiniscus and Batillipes, 

 but it possesses the palps near the mouth, which those genera lack. 



Further small differences from typical Echi7iiscus are found 

 in the lack of eyes, and in the thickening of the anterior pair 

 of cirri near the mouth. 



In the original drawings (25) the enlarged detailed figure of 

 the teeth and pharynx was accidentally omitted, and in con- 

 sequence of this there was no mention of the bearers in the 

 text. These omissions are remedied here. 



One species of Echiniscus, otherwise quite a typical member 

 of the genus, possesses teeth, gullet, bearers and pharynx 

 exactly like those of Oreella. It was discovered to have these 

 peculiarities by Herr Thulin, of Lund, Sweden, and although 

 I believe the animal to be E. intermedius Murray (25) the 

 identity is not yet proven.* 



On the Relationships of the Various Genera. 



The two great types of Tardigrada, the only two which represent 

 extensive groups, Echiniscus and Macrohiotus, seem sufficiently 

 diverse, while Milnesium stands pretty remote from both. 



Eclmiiscus is armour-plated, possesses various setae on the 

 head and commonly on the body ; has straight teeth without 

 bearers, and has no chitinous rods in the pharynx. The claws 

 are not joined in pairs. 



Macrohiotus is unarmoured, has no setae on the head, usually 

 none on the body ; the teeth always have bearers, and there are 

 always chitinous rods in the pharynx. The claws are always 

 joined in pairs. 



The two groups differ throughout their whole structure. 

 Recent discoveries of aberrant species in each group have broken 



* The doubt as to the identity is now removed, as specimens just found 

 (March, 1911) by the Clare Island Survey in W. Ireland possess bearers. 



