ISOPODS OF NORTH AMERICA. 525 



could be discovered on the thoracic segments of the pleural lamellae, 

 which in Palsegyge are said to be 'rudimentaires et a peine visibles.' 



"The antennules (inner antennae) are short, conical, composed of 

 three joints and bearing a few minute setae at the tip. The antennas 

 (outer antennae) are composed of five joints, of which the first is indis- 

 tinctly njarked off from the lower surface of the head; the third is 

 longer and. much more slender than the second, the fifth is very 

 minute. The mandibles, which are embraced by the upper and lower 

 lips to form the characteristic 'beak' of the Epicaridea, are of the 

 usual shape. The first pair of maxillae appear to be absent. After a 

 careful examination we have been unable to find any^ distinct rudi- 

 ments of them, though the triangular areas between the base of the 

 mandibles and the lower lips on each side bear some resemblance to 

 the rudiments of these organs in Palsegyge (Giard and Bonnier, in the 

 work mentioned, pi. v, f. 2). The rudiments of the second maxillae 

 are to be detected further back on the under surface of the head. 

 Immediately in front of each a relatively large opening leads into a 

 capacious tube lined by an imagination of the chitinous cuticle, the 

 protuberance interpreted as the rudiment of the second maxilla form- 

 ing the lower or posterior lip of this orifice. 



"Unfortunately, these tubes were not discovered till the soft parts 

 of the head had been removed by caustic potash, so that we are unable 

 to say anything as to their connections inside the body. This is the 

 more to be regretted since we know of nothing analagous to these 

 organs, not only in the Epicarldea but even among the Malacostraca. 



"The maxillipeds are similar to those of Palxgyge, but somewhat 

 narrower. Each consists of a flat, roughly quadrangular plate par- 

 tially divided into two parts by an oblique line. . The posterior part 

 has its external angle rounded and pointed as in Pals&gyge borrei, 

 and the antero-internal angle is produced. The anterior margin of 

 the maxilliped bears a few setae, and at its inner angle is articulated 

 the small 'palp,' also setose. 



"Posteriorly, the lower surface of the head terminates in a freely 

 projecting lamina, the ''limbe posterieur^ of Giard and Bonnier. In 

 the present species this lamina is cut up into a fringe of digitate 

 processes, commencing on each side a little way from the middle line 

 and increasing in size outwards. Externally, on each side the lamina 

 is produced into a long process, narrowing gradually from its base to 

 a rounded tip, turned inwards and extending beyond the middle line. 

 In Pald&gyge there are two pairs of shorter processes and no fringe of 

 minute digitations. 



"The thoracic legs are all similar and of the usual structure. The 

 'adhesive cushions' present on the proximal segments of the first pair 

 in Palcegyge are here absent. The oostegites or brood lamellae were 

 unfortunately injured in the single specimen found. The usual five 



