180 BRITISH ENTOMOSTRACA. 



derable size ; the second is nearly equally large ; the third 

 is short, about half the size of preceding ; and the fourth 

 is more slender, but considerably larger than the third. 

 The second is beset on both upper and lower edge with 

 numerous stout setse, and from the junction of the third 

 and fourth there issues two or three long, slender fila- 

 ments ; while the last joint is terminated by several strong 

 serrated spines. 



The natatory foot (t. XXII, f. lb) is a remarkable 

 organ. It is composed of eight articulations. The 

 first, or basilar joint, is very large, fleshy, and of a 

 rounded oval form. The second joint is very narrow, com- 

 pared wdth the first, and about one third of the length; 

 wdiile the remaining six are short, the whole scarcely 

 equalhng the second in length. From the base of each 

 of these seven articulations issues a long filament, whilst 

 from the anterior margin of the basilar joint there springs 

 an appendage, consisting of two nearly equal, slender 

 joints, the latter terminating in two blunt, crooked claws. 



The first pair of jaws consists each of a square-formed 

 plate, furnished on the inferior edge with three or four 

 finger-like appendages, each provided with several short, 

 but stout setae, and having attached to its upper margin 

 a large triangular-shaped plate, armed with about fifty fila- 

 ments of considerable length. The second pair (t. XXII, 

 f. 1 d, d) is composed each of a short, stout body of three 

 articulations. The first joint is rather broad ; the second 

 larger, and furnished on its lower edge with three rounded 

 finger-like bodies, each of which sends oft' several short 

 setse, while the third is very short and conical, and sends 

 off" about eight stout, somewhat serrated spines from its 

 extremity and lower margin. 



The oviferous feet (t. XXII, f. 1/) are organs of a very 

 pecidiar appearance and structure. They are long, cylin- 

 drical, slender, and of a twisted form. They are each divided 

 into very numerous short articulations, and armed at the 

 free extremity with about eight or ten short, sharp-pointed 

 spines, which again arc in their turn provided with several 



