MARINE ISOI'ODA OF NEW KN(iLANI), ETC. 369 



tbi.s habit may be distinguished from the- other marine Isopod.s of our 

 cons!. 



The head is rounded in front, with an elevated margin, and a, slight inc- 

 di;in projection between the, bases of the antennnhc. The eyes are 

 sm;dl and Sab-triaDgular, widely separated. The antennnhe and the, 

 :inlenn:e :ire inserted on the inferior surface of the head, and, when the 



.innii.ii contracts, they, are received into a groove along the margin of 

 the he:id mid anterior tlioracic segment. The antennulae (pi. IX, fig. 54 a) 

 liiive. the basal segment large, the nccond segment small and conical, 

 the third slender, cylindrical ; the, flagellum about ten-jointed, ciliated, 

 shorter than the peduncle. In the antenna; (pi. IX, fig. 5-1 h) the peduncu- 

 lar segments decrease but little in diameter, and increase in length from 

 the, first to the, fifth, and are followed by a flagellum about as long as 

 the peduncle, tapering from the base,, with the basal segments strongly 

 ciliated along their inner or anterior distal margins. The antenna- aro 

 separated at the base by a triangular, somewhat projecting epistome, 

 which also partly separates the bases of the antcnnnhc. The, maxilli- 

 peds have the basal segment short and somewhat triangular, with plu- 

 mose seta} at the acute, apex, and a five-jointed palpus, of which the, first 

 segment is short and smooth, ami the, following segments strongly ciliated 

 along more or less of their inner margins. The outer maxillae are termi- 

 nated by three ovate rather acute lobes, which are strongly ciliated. The 

 inner maxilla) have the inner lobe tipped with four pectinated curved 

 set jr., and the outer armed with strong denticulated spines. The, mand- 

 ibles are robust and bear on their external surface at the apex a dentig- 

 erous lamella, or usually two such on the right mandible, receiving the 

 lamella of the left between them ; below the lamella is a strongly ciliated 

 ridge supporting the dentigerous lamella and connecting it with the mo- 

 lar process, which is large and strong. The, inandibnlar palpi are slender, 

 with t he last segment sub-sem (circular, bearing at its apex a few serrated 

 spines, and below a comb of straight setae; the middle segment bears a 

 similar comb with stouter spiny setae at the ends. 



The first thoracic segment is longer than the others, and much elon- 

 gated at the sides, embracing the head as far as its anterior margin. 

 Above this lateral expansion on each side the segment is excavated for 

 a projecting lobe of the head behind the eye. The second, third, and 

 fourth segments are somewhat shorter than the first and longer than the 

 lift h, six) h, and seventh. The, margin of the last segment bends slight ly 

 backward at the middle. In the thoracic segments behind the first the 

 epimeral sutures are indicated by a faint depressed line, below which 

 the, lateral margin of the second segment tapers to an obtusely rounded 

 point, the third is more acutely pointed, the fourth oblique and acute 

 behind, the fifth and sixth also oblique but less acute, and the seventh 

 rounded. The legs are weak, hairy, and much alike throughout, formed 

 for walking, and none of them chelate. The dactyl us in all is short and 

 robust, armed with a stout curved spine or claw at the tip, and a smaller 

 24 F 



