272 THE INTERCHANGEABLE RELATIONS OF 



This worm-shaped figure, (A) Linguatula, represents an an- 

 imal which was at one time classed among the intestinal worms, 



Fig. 170 (A). Linguatula probosculea. Rud. About half natural size. At 

 the broad end, which is the head, are a few recurved hooks. From Quatre- 

 fages. 



Fig. 171 (B). The young of fig. 170, just hatched. Highly magnified, m, 

 the mouth ; 6, the bristles which are protruded from the mouth, and are used to 

 pierce the tissues of animals; cl, the two pairs of hooked feet. From Van 

 Beneden. 



Fig. 172 (C). Anchordla uncinata. Mull. Natural size about ^ of an inch 

 long. The male, m, the mouth ; an, an 1 , the two pairs of feelers ; cl, the two 

 pairs of hooked feet. From Nordman. 



Fig. 173 (D). Nymphon grossipes. Magnified considerably. A very young 

 individual, seen in profile. /;, the head; an, the pincer-like claws; an 1 , the 

 hooks of an ; an 2 , one of the feelers ; cl, the hooked feet. From Kroyer. 



Fig. 174 (E). Phytoptus,^.! Dujardin. 150 diam. One of the Tardi- 

 grada with only two pairs of legs (cl) ; A, the head ; cl, the legs ; eg, the eggs. 

 From Dujardin. 



Fig. 175 (F). Demodex fnlliculorum. 150 diam. A view of the lower side 

 of a worm-like Spider-mite, which lives as a parasite, buried in the skin at the 

 roots of the hairs of animals, and thereby forming a pustule ; m, the mouth ; cl, 

 the four pairs of feet; a&, the abdomen. Original! y from Simon. 



Fig. 176 (G). Epeira trifolium. Hentz. Natural size. For description of 

 lettering see fig. 129, p. 220. 



Fig. 1 77 (H). Myzostoma cirrhiferum. Leuck. Natural size about -^ of an inch 

 long. An external parasite on a kind of starfish (Comatula). A view from below. 

 m, the mouth ; m 1 , the proboscis protruded from m ; m 2 , the aperture of m' ; ph, 

 the throat; ph to an, the whole length of the intestine; v, v l , u 2 , the branching 

 prolongations from the intestine; n, the concentrated nervous mass, which gives 

 off branches toward the head and tail, and to the five pairs of hooked feet (cl) ; 

 ot- 2 , 0y3, Ol ,4 t the right and left V-shaped male reproductive organs ; ov, ov^ the 

 apertures of the last ; pe, pe'*, the right and left oviducts through which the eggs 

 (w, w) pass when laid; pe*, the common aperture of pe, pe* ; cl, the five pairs 

 of short, jointed, hook-tipped legs ; sk, ski, s& 2 , the four pairs of suckers, or 

 sucker-like organs of adhesion. 



Fig. 178 (I). Tardigrada, sp. ? Duj. 160 diam. A profile view of a Tar- 

 digrade which has four pairs of short, clawed legs (cl) ; m, the mouth ; th, the 

 throat; /, the gizzard or internal jaws; st, the intestine ; an, posterior end of 

 st. From Dujardin. 



Fig. 1 79 (J). Lydella, sp.? Duj. 600 diam. A Tardigrade which has four 

 pairs of long and distinctly jointed legs (cl) ; ///, the throat ; /, the gizzard-like 

 internal jaws. From Dujardin. 



