CANTHOOAMPTUS. 53 



small ffig. 9). Inner segment of the basal joint of the 

 fifth pair of feet (fig. 10) in the female , elongated, 

 fringed, bearing two long and three short apical setae ; 

 second or outer joint sub-ovate, finely fringed intern- 

 ally; externally bearing six long marginal setae. In 

 the male the limb is smaller, the basal joint short, 

 broad, and having six short setae of equal length 

 (fig. 11) ; second joint nearly like that of the female. 

 Caudal segments (fig. 12) somewhat longer than 

 broad ; inner seta about twice as long as the 

 outer ; anal operculum denticulated. LeDgth ^th of 

 an inch ('65 mm.). 



G. hibernicus occurs plentifully in the Mullingar 

 Canal at Dublin, and in a lake near Newport, county 

 Mayo ; for specimens from both of these places I am 

 indebted to my friend Mr. David Robertson, of Glasgow. 

 From 0. minutus, which must be considered as the 

 type of the genus, it differs essentially in having the 

 inner branch of the fourth foot 3-jointed ; but in all 

 other important particulars its characters are those of 

 a true Canthocamptus. 



3. CANTHOCAMPTUS PALUSTEIS, nov. sp. PI. XXXIX, 



figs. 1323. 



Anterior antenna of the female slender, 8-jointed ; 

 second joint the largest ; last two much more slender 

 than the rest (fig. 13). In the male it is more robust, the 

 fifth and sixth joints coalescent (fig. 14), and forming 



