92 THE VOYAGE OF H.M.S. CHALLENGER. 



its outer margin, and having the three outer setae dilated and spathulate at the bases. 

 The setae are all nearly equal in length ; those of the left segment are not spathulate, nor 

 are any of those of the male animal. The upper eyes are closely approximated, larger in 

 the male than in the female. 



Habitat. — Off Port Jackson, Australia ; abundantly between Api and Cape York ; 

 Philippine Islands (February 6, 1875) ; abundantly in the Pacific, north of the Sandwich 

 Islands ; in several gatherings from the North Atlantic near the Cape de Verde Islands, 

 and near the Ki Islands, Australasia. This appears to be one of the commonest and most 

 widely-distributed of the Pontellce, and there can be no doubt, I think, of the identity of 

 the species described separately by Prof. Dana and Sir John Lubbock, 



4. PonteUa plumata, Dana (PI. XXXVII. figs. 1-11). 



Pontellina plumata, Dana, Crustacea, XL S. Expl. Exped., p. 1135,. pi. Ixxix. fig. 10, a.-d. 

 „ twrgida, (J, idem, ibidem, p. 1136, pi. Ixxix. fig. 11, a.b., fig. 12, a.I>. 



Length, I-12th of an inch (2 - l mm.). Cephalothorax of the female, seen from 

 above, very broadly ovate, scarcely twice as long as broad, rounded off in front, posterior 

 lateral angles rounded or scarcely angulated, rostrum slender, adpressed; figure of the 

 male rather less tumid. Anterior antennae (fig. 2) about as long as the body of the 

 animal, twenty-one-jointed (?), slender, sparingly setose, most of the joints bearing one 

 or two small apical and marginal setae, and several of them — notably the fourth, fifth, 

 sixth, thirteenth, fourteenth, fifteenth, eighteenth, and twentieth, having also single long 

 ciliated setae, the last joint having four long terminal setae of the same character ; the 

 central joints of the right antenna in the male (fig. 3) are very much and abruptly 

 swollen, the first of the swollen joints bearing a rigid, geniculated seta, the last a 

 strong tooth and a series of fine marginal setae ; the limb beyond this point — being at 

 least half its length— is divided into three very long and slender joints, the first of 

 which is finely setiferous or denticulated throughout its entire length, while the next 

 j oint bears a short, sub-crescentic series of about twelve similar setae on its upper half ; 

 between these two joints the antenna is hinged. The setae of the posterior antennae in 

 the female (fig. 4) are profusely plumose, remarkably long, and reaching, in the natural 

 position of the limb, nearly, if not quite to the extremity of the body of the animal 

 (fig. 1) ; the secondary antennal branch is about half as long as the primary. The two 

 1 tranches of the mandible-palp are respectively two- and three-jointed (fig. 5), and their 

 setae are also extremely long. Posterior foot-jaw very small. The first pair of swimming 

 feet (fig. 6) has its inner branches three-jointed, the outer marginal spines very slender; 

 the terminal spines of the following pairs of feet (fig. 7) are straight and narrow, with 

 finely pectinated margins. In the male, the fifth foot (fig. 9) of the right side has the 

 third joint broadly quadrate, with a strong, falcate, lateral process, the terminal claw 



