J. MURRAY ON WATER-BEARS, OR TARDIGRADA. G5 



M. tardigrad/um was supposed to have one of the lower claws 

 three-pointed and the other two-pointed ; M. alpigenum had all 

 the lower claws three-pointed. 



The number of points is, however, variable. In Scotland we 

 may find lower claws with one, two, and three points on the same 

 animal. In some other regions they appear to be more constant, 

 and all the examples will have the same number of points (two 

 or three, as the case may be) on the lower claws of all legs. 



Genus Echiniscus Schultze (Figs. 10—13) (41). 



The back is covered by a series of plates or shields, sym- 

 metrically arranged (as shown in Figs. 10 and 12). There are four 

 small bristles, arising from papillae, near the mouth, and two 

 blunt palps (Fig. 10). At the base of the head is a pair of longer 

 setae {a, Fig. 10), usually curved forward and looking very like 

 cows' horns. The teeth are long and straight, and have no 

 bearers. There are generally no rods in the pharynx (doubtfully 

 present in one or two species). There are four claws on each 

 foot (two only in all the larvae known), all free and about equal 

 in size. 



The two inner claws of each foot have usually a decurved 

 spine or barb on the under surface, while the outer claws have 

 no barb (Fig. 11). Occasionally, the outer claws also have barbs, 

 which are straight, not decurved (Fig. 13). A few species have 

 no barbs on any claws. 



The fourth legs have usually a fringe of spines or tooth-like 

 processes, absent from only a few species (Fig. 10, F). 



The first leg has, in most species, a small spine (Fig. 12). The 

 fourth leg has in most species a blunt palp at the base (Figs. 10 

 and 12). 



The texture of the plates is characteristic ; they may be 

 smooth (rarely), punctate with pellucid dots (of uncertain nature), 

 papillose, pitted, or reticulate with raised lines. 



The eggs are always smooth, and are laid in the cast skin. 



The body of Echiniscus is supposed by Richters to consist of 

 six segments (see Figs. 10 and 12, I. — vi.). The genus is 

 divided into two groups, in one of which segments v. and vi. 

 remain distinct (Fig. 12) ; in the other, v. and vi. are completely 

 fused together (Fig. 10). 



Journ. Q. M. C, Series II. — No. 60. 5 



