MARINE ISOPODA OF NEW ENGLAND, ETC. 425 



inuer ramus is five-jointed instead of six-jointed, as in L. algicola, from 

 which species the males are easily distinguished by the elongate and 

 slender antennuliij and chelate legs, and by other characters, as may be 

 seen from the following description and the figures. 



The males (pi. XIII, fig. 89) are remarkable for the long, slender hand 

 terminating the first pair of legs (pi. XIII, fig. 90). The body of the male 

 is short and robust, and the segments are well separated by constric- 

 tions at the sides. The head with the united first thoracic segment is 

 short and rounded, bulging strongly at the sides just behind the eyes, 

 which are conspicuous, considerably less in diameter than the bases of 

 the antennidiie, distinctly articulated and coarsely faceted. The anten- 

 luiliB are much elongated, especially in the basal segment, which con- 

 Btitutes nearly half the length of the organ, and is more than one-third 

 as long as the body; this segment is straight, swollen on the inner side 

 near the base, then tapers gradually to the tip ; the second segment is 

 a little over one-third the length of the first and cylindrical ; the third 

 is again about one-third the length of the second, and scarcely thicker 

 than the following flagellar segments, which vary in number from six to 

 eight, and are usually of about equal length. In case there are eight 

 flagellar segments the first is, sometimes at least, considerably shorter 

 than the others. The last segment is tipped with a rudiment, and bears 

 a few setse. The whole number of segments, therefore, varies from nine 

 to eleven, and if one of the flagellar segments be taken as a unit of 

 measurement, the length of the first three segments will be approx- 

 imately expressed by the numbers 9, 3.8 and 1.4. The antennae when 

 extended do not far surpass the middle of the basal segment of the 

 antennulse, and are comparatively slender; the first segment is short 

 and somewhat expanded distally; the second is slightly longer and 

 exi:)andedso as to be sub-cordate; the third is short and cylindrical, equal 

 in length to the first ; the fourth is the longest segment, being longer 

 than the first three taken together, and is slender and cylindrical, with 

 a few setse near the tip; the fifth is more slender and but slightly 

 shorter than the fourth, and is tipped with a minute rudimentary ter- 

 minal segment and a few setae. 



The legs of the first pair are large and much elongated. They vary 

 somewhat in size and proportions, but are commonly, when extended, 

 longer than the body of the animal. In these legs the segments pre- 

 ceding the carpus are robust but comparatively short, while the carpus 

 is about half as long as the body, and the propodus (pi. XIII, fig. 90) is 

 even more elongated than the carpus, and is usually strongly flexed 

 upon it. More than half the length of the propodus is made up of the 

 slender digital process, which bears, near the base on the inner side, a 

 low, obtuse tooth, and a larger and more prominent one near the slender 

 incurved tip. The dactylus (pi. XIII, fig. 90) is more than half as long 

 as the propodus, slender, curved, and pointed, and armed with scattered, 

 weak spinules along the inner margin. The digital process of the pro- 



