BY MARGUERITE HENRY. 555 



elongated and slightly expanded at the base; caudal rami short and broad, some- 

 what dilated near their tips, their inner edges finely ciliated; the innermost seta 

 of each ramus is very delicate, the other five are large and densely hairy. An- 

 teunules composed of twenty-five segments and reaching beyond the first seg- 

 ment of the- abdomen. Fifth pair of leg's with the second segment of each exo- 

 podite produced inwardly to form a slightly curved process, 3rd segment very 

 small, bearing two spines of unequal length; the endopodite, composed of one 

 segment, nearly reaches the end of the first segment of the exopodite. Length, 

 1.8 mm. 



Blale. Similar to the female in shape, except that the caudal rami are 

 slightly narrower. Right antennule very swollen in the middle portion. In the 

 fifth pair of legs, the right leg has a small one-segmented endopodite and a two- 

 segmented exopodite, the terminal segment of the latter bearing a short spine 

 and a curved apical one; left leg with its exopodite bearing two digitifoi-m pro- 

 cesses and a rounded ciliated lamella. Leng-th, 1.5 mm. 



Distribution. — N.S.W. : Casino; Queensland; Ceylon; Natal. 



Family CENTROPAGIDAE. 



Caudal rami more or less elongated, bearing the full number of setae. An- 

 tennules in the female composed of 24 or 25 segments; right antennule in the 

 male geniculate. Four first pairs of legs with both rami S-segmented ; fifth 

 pair in the female biramous, natatory; in the male the exopodites transformed 

 and dissimilar, the right leg being the stronger. Five genera of this family are 

 represented in Australia but only three of them are known to occur in New 

 South Wales. 



Key to the genera of Centropagidae. 



A. Natatory legs with the number of segments in the endopodites reduced. 



B. Endopodites of the first pair of legs one-segmented Bnmella. 



BB. Endopodites of first pair two-segmented C alamoecia. 



AA, Natatory legs with the endopodites three-segmented. 



B. 4th pair of legs in the female with a long spine on the inner edge of the 



basal segment Gladiofei e)/s. 



BB. No such spine. 



C. 5th pair of legs in the male with the exopodite of the left leg 



prehensile, ending in a long claw Boeekella. 



CC. Exopodite of the left leg scarcely prehensile, bearing a simple 

 spine at the tip Hemiboechella. 



Genus B E c K E L L A De Guerne and Richard, 1889. 



^■^n.—Boeckia Thomson, 1882. 



Last segment of the cephalothorax greatly produced laterally. Abdomen 

 composed of five segments in the male, three in the female; caudal rami short. 

 Five pairs of legs in the female, all natatory, and with both rami three-segmented ; 

 fifth pair with the second joint of the endopodite produced inside; fifth pair in 

 the male very powerful, each leg terminating in a long movable claw, the endo- 

 podites rudimentary. About twenty-seven species are known and, with the ex- 

 ception of Boeekella orientaUs Sars, which occurs in Central Asia, they are all 

 confined to the southern hemisphere; seven species are found in New South 

 Wales. 



