J. MURRAY ON WATER-BEARS, OR TARDIGRADA. 63 



of each pair closely welded for about half the length of the longer 

 claw, and the two pairs similar (Fig. 9) ; (3) claws of each pair 

 very unequal, firmly joined at base, the two pairs similar (Figs. 7 

 and 8) ; (4) the two pairs dissimilar — one short, nearly equal, 

 and firmly joined, the other with a very long filiform claw, laxly 

 joined to the back of a shorter claw (Fig. 4). 



The organs for inbibing food are illustrated in Fig. 5. They 

 are, — a funnel-shaped mouth, M ; a tubular gullet, G ; the teeth, T ; 

 and the pharynx, P. The teeth have needle-like or lancet-shaped 

 points, which are seen in the figure entering the mouth. 

 They are greatly enlarged behind, and form there a large furca, F 

 (better seen in Fig. 1a). They are supported from the gullet by 

 a pair of sigmoid rods, the bearers. They are guided into the 

 mouth by the tooth-sheaths or guides, 8, The pharynx is a 

 muscular bulb, P, shortly or narrowly elliptical. The gullet 

 passes a short distance into it, and is expanded at the end into 

 a flange. Surrounding the central canal of the pharynx are a 

 number of chitinous bodies, in the form of rods or nuts, 11. These 

 are in six rows, the rows approximated in pairs, and there are 

 two, three, or four rods in each row. The last in each row is 

 commonly smaller, and is called the comma, C. Many species 

 have no comma. On the end of the gullet are three processes, 

 called by Doyere the apophyses (A), which alternate with the 

 double rows of rods. The two first rods after the gullet are 

 sometimes joined and sometimes free in the same species. 



Individuals of Macrobiotus are very commonly found which 

 have no rods in the pharynx, and with greatly reduced teeth, or 

 even with no teeth at all, and no gullet or pharynx. These are 

 in a peculiar condition, which I can hardly regard as permanent, 

 the " simplex form " of Richters, the genus Doyeria of Plate. 

 Most species are known to have these forms, and they are found 

 even in the egg, but nothing is understood about them. 



The skin is usually smooth, but may be papillose (Fig. 2, 

 M. aminhitus), tubercled (J/, tuherculatus), or spiny (J/, ornatus). 

 The eggs, when laid in the skin at the time of moulting, are 

 smooth and oval ; when laid free they are spiny or tubercled, and 

 round, rarely elliptical ; in one species only oval and viscous 

 (without spines). 



More than thirty species of the genus have been described, and 

 twenty-one of these occur in Britain. 



