TALITRUS LOCUSTA. 19 



food from fixed positions — a circumstance, according to 

 Leach, from which it has earned the sj)ecific name of 

 Locusta. 



The first pair of legs are simple, the terminal joint 

 being slightly curved, but not having the power to 

 impinge against the preceding. They are strong and 

 efficient for the purpose of burrowing or hooking to any 

 substance, but have no prehensile capability. 



The second pair of legs are feeble, of a membranous 

 appearance, and generally lie folded up close beneath the 

 body. The terminal joint is short, almost obsolete, and 

 placed at a considerable distance from the extremity of 

 the preceding, appearing to be an inefficient organ.* 



The two next succeeding pairs of legs are strong and 

 efficient members for perambulation, but they are not so 

 powerful as the last three pairs. 



The first or scale-like joint affixed to the sides of 

 the body, is largely developed in each leg. That of the 

 fifth pair of legs is bilobed, and is anteriorly nearly as 

 deep as the one that precedes it. 



The swimming fins are short, being never required, 

 since the animal never voluntarily seeks the sea. The 

 lateral appendages of the tail are short and stout. These, 

 with all the other limbs except the second pair of hands, 

 are furnished with fasciculi of short, spine-like hairs. 

 These hairs are generally blunt at the tip, and furnished 

 laterally with a slight secondary appendage, about one- 



* In Milne-Edwards' figure of the male of T. saltafor, stated to have been 

 copied from the living specimen (R. An. Ed. Crochard, Crust., pi. 59, fig. 2a), 

 the second pair of legs is represented as evidently larger than the first pair, 

 but destitute of spines. This figure, therefore, appears to us rather to repre- 

 sent Talitrus Beaucoudraii of M. -Edwards. 



It must be borne in mind that, throughout the Amphipodous portion of 

 this work, the limbs on one side of the body are alone represented, in order 

 to prevent confusion ; the opposite limbs being identical in structure. 



c 3 



