A REVIEW OF THE MYSIDACEA 141 



is attained mainly by the large size of the sixth joint which is one- 

 quarter longer than the fifth and four times as long as broad; it is 

 widest just distal to the middle and from this point the joint narrows 

 considerably, the distal portion of the inner margin being slightly 

 concave and armed with numerous spiniform setae; the outer distal 

 margins are also armed with numerous setae ; the seventh joint is about 

 one-fourth of the length of the sixth and terminates in a strong some- 

 what curved nail; the outer margin is convex and the inner margin 

 concave and fringed also with spiniform setae ; the inner face of this 

 joint is armed with numerous very strong setae, which are barbed on 

 one side only ; the concave inner margin of the seventh joint folds down 

 against the distal portion of the inner margin of the sixth joint to form 

 a kind of subchela to the limb ; in the male specimens, which are im- 

 mature, the second thoracic limbs have the same general form as in 

 the female here described, but they appear to be less robust and the 

 subchelate appearance of the limbs is less well marked. 



Remaining thoracic limbs with the carpopropodus of the endopod 

 (fig. 50, g) divided into two subjoints by a transverse suture; seventh 

 joint very short and terminating in a long slender nail. 



Sixth abdominal somite one and two-thirds as long as the fifth. 



Telson (fig. 50, h) as long as the sixth abdominal somite, one and 

 a third times as long as broad at the base and three times as long as 

 the breadth at the apex, entire and broadly linguif orm in shape with 

 the apex broadly rounded ; lateral margins with about 12 short stout 

 spines distributed along the whole length ; apex armed with 3 pairs of 

 long strong spines, the inner pair equal in length to one-third of the 

 telson, the next pair slightly shorter and the outer pair only one-fifth 

 of the telson in length ; no plumose setae on the apex. 



Inner uropods 1% times as long as the telson, with five spines on 

 the inner lower margin in the region of the statocyst ; outer uropods 

 slightly longer than the inner. 



Length of adult specimens 7.5 mm. 



Occurrence. — East coast of United States: Woods Hole region, 

 1 male, 1 female; Calcasieu Pass, La., W. H. Spaulcling collector, No. 

 19, 7: 30 p. m., September 19, 1907, 4 males, 4 females; Bache station 

 10157, latitude 36°46' N., longitude 75°38' W., January 20, 1914, 2 

 specimens; Bureau of Fisheries Survey of Chesapeake Bay, 1920, sta- 

 tions 8888, bell buoy No. 1, SE. i/ 2 E. 1 mile, buoy 10C, NW. by W. 

 y 8 W., off Sandy Point, 8 fathoms, gray sand, October 20, 1920, 1 

 adult female, 7 mm., 1 immature male, 4.5 mm.; 8895, lightship S. 

 % E., Cape Henry Light S. % W., whistling buoy SW. by W. V 4 W., 

 16!/2 fathoms, mud and sand, October 21, 1920, 1 adult male, 7.5 mm.; 

 8896, Cape Henry Light SW. by S. % S., lightship N. % W., 23 

 fathoms, sand and mud, October 21, 1920, 2 males, 5 to 6 mm. ; 8890, 



