300 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



Head broader than long; eyes situated post-laterally. First pair of 

 antenna? with the first two peduncular joints large, the second half as 

 long as the first; the third joint long and slen- 

 der, twice as long as second joint; flagellum 

 consists of seven joints. The first two pedun- 

 cular joints of the second pair of antenna- are 

 of equal length; the following three are of equal 

 length and longer than the first two; the fiagel- 

 lum consists of about seven joints, and extends 

 to the posterior margin of the third thoracic 

 segment. 



The thoracic segments are of equal length, 

 with the exception of the first, which is slightly 

 longer. The seventh segment is produced back- 

 ward in two rounded lobes, one on either side 

 of the median line, and close together. ' 



The first abdominal segment has two suture lines at either side, 

 indicative of coalesced segments. The terminal segment is very con- 



FIG. 319. DYNAMENE PER- 

 FORATA. LAST TWO THO- 

 RACIC SEGMENTS AND AB- 

 DOMEN. 



FIG. 320. DYNAMENE PERFORATA (AFTER MOORE), a, FIRST ANTENNA. 6, SECOND ANTENNA, c, 

 MALE, d, TIP OF MAXILLA, e, MANDIBLE. /, MAXILLIPEDS. g, FOURTH LEG. h, FIRST LEG. i, 

 SEVENTH LEG. j, PART OF TERMINAL SEGMENT OF ABDOMEN WITH UROPOD. 



vex at the base, and has four small tubercles, forming a square on the 

 convexity. Its apex has a heart-shaped opening, formed by the pro- 



