ISOPODS OF NORTH AMERICA. 325 



article of the second antennae is short, and does not extend beyond the 

 antero-lateral angles of the head; the second article extends to the 

 end of the first pair of antennae; the third article is three times as 

 long as the second article; the fourth is twice as long as the third; the 

 fifth is a little shorter than the fourth. The flagellum is composed of 

 three articles. The second antennae are not quite as long as the body, 

 being 14 mm. in length. The maxilliped has a palp of five articles. 

 The palp of the mandibles is wanting. 



The first segment of the thorax is a little longer than the two fol- 

 lowing segments, which are subequal. The fourth segment is 

 extremely long, being 6 mm. long, or 1 mm. longer than all the other 

 six segments taken together. This segment is broader anteriorly than 

 the preceding segments; at its posterior extremity it becomes abruptly 

 narrower. The fifth segment is about one-sixth as long as the fourth 

 segment; the sixth segment is about equal in length to 

 the fifth; the seventh is a little shorter than the sixth. 

 The lateral parts of the first segment are broadly ex- 

 panded and surround the posterior portion of the head, 

 the antero-lateral angles extending as far as the eyes. 

 The epimera are distinctly separated on all the six follow- 

 ing segments. On the second and third segment they 

 are small and occupy the whole of the lateral margin. 

 On the fourth segment they occupy the antero-lateral 

 angles. In the last three segments they project at the 

 sides in acutely pointed processes. FIG 356 _ ASTA 



The first two segments of the abdomen are short. The CILLA GRANU- 

 terminal segment is long and narrow, about one-fifth 

 the entire length of the body, being 3 mm. long. It is 

 produced to a narrow, obtuse extremity. Near the base there is a 

 transverse depression marked at the sides by an acute process or 

 expansion of the lateral margin. 



The first four pairs of legs are slender, directed forward, densely 

 covered with long hairs on the inferior margins of all the articles. 

 The first pair are much shorter than the three following pairs, which 

 are gradually increasingly longer. The last three pairs of legs are 

 ambulatory and gradually decrease in length. 



The whole surface of the body is covered with small granulations. 

 On the posterior portion of the dorsal surface of the head are two low 

 tubercles. The three last segments of the thorax have each one low 

 tubercle in the median longitudinal line. The first two segments of 

 the abdomen have each two low tubercles, one on either side of the 

 median longitudinal line. The terminal segment has a double row of 

 six low tubercles in two longitudinal series, one row on either side of 

 the median line. 



