96 
ZOOLOGY. 
ing the food, which the horseshoe obtains by burrowing in the mud 
or sand. The mouth is situated between the second pair; the first 
pair of legs are smaller than the others. All end in two simple 
Fig. 120.— Actual section through the head of Limulus, shq^lring the second pair 
of appendages and their relations to the shell or carapace, /if, hearty iiv, 
liver; end, appendage homologous with the endopodite of Decapoda. 
Fig. 121.— Section through the abdomen of Limulus. c, carapace; ht, heart; mf, 
intestine; ng, ganglia (lettering being the same as in Fig. 123); en, axial, 
jointed endopodite; ex, exital or respiratory portion bearing the gill-lamellae; 
the outer division {ex) homologous w^ith the exopodal portion of the Phyllo- 
pod and Phyllocaridan leg. 
I laws (Fig. 120), except the sixth pair, wliich are armed wiLth several 
spatulate appendages serving to prop the creature as it burrows into 
the mud. Appended to the abdomen are six pairs of broad swim- 
ming feet (Fig. 121, ex\ of which all but the first pair bear on Xhi^ 
