396 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



this convexity rapidly diminishes so that the fourth has nearly a trans- 

 verse margin and tlie last three segments become concave behind in an 

 increasing degree. The epimera are narrow and obtusely pointed behind, 

 and do not surpass the posterior angle of the segment to which they are at- 

 tached except in the last two segments. The first pair of legs (pi. XI, fig. 

 67 d) are short and stout, the basal segment large but short; the next 

 three segments short and with little motion on each other; the propodus 

 stout and somewhat curved ; the dactylus long, curved, and strong. The 

 second and third pair of legs are much like the first, as are the four suc- 

 ceeding pairs, but somewhat larger and longer. The seventh pair (pi. XI, 

 fig. G7e) have the basal segment about twice as long as in the first pair, 

 and the succeeding segments are also proportionally longer than in the 

 first pair, except the dactylus, which is slightly weaker and not longer 

 than in the first pair. 



The pleon tapers rapidly at the sides; its first five segments are sub- 

 equal in length; the last segment forms about half its length, and is flat 

 and broadly rounded behind. ITropods (pi. XI, fig. 67/) surpassing the 

 telson with the basal segment, about as long as the rami and but little 

 produced at its inner angle; outer ramus linear oblong, rounded at the 

 end ; inner ramus shorter and broader, oblique at the tip. 



Length 17-22™™, breadth 10-12"™. These animals when preserved 

 in alcohol are of a leaden color, with the posterior margins lighter. 



They are often parasitic on the blue-fish [Pomafonms saltatrix Gill). 

 The details figured on plate XI are from small specimens collected on 

 young blue-fish at Xew Haven !, by Mr. F. S. Smith. Other localities are 

 Thimble Islands!, Long Island Sound; Vineyard Sound!, Fish Commis- 

 sion 1871, one specimen among scup {Stenotonnis argyrops Gill). A 

 specimen was sent to the Museum in 1878, collected by Dr. T. H. Bean, 

 from the gill of Microjyogon undulatus caught at Xorfolk !, Va., July 9, 1878. 



Specimens examined. 



2071 

 2072 

 2073 

 2074 



2075 

 207G 



Locality. 



Norfolk, Va , 



New Haven 



Vineyard Sound 

 do 



Vineyard Sound . 



Parasitic on — 



Micropogon . 



Blue-fish 



...-do 



Scup 



Blue-flsh. 



When col- 

 lected. 



July 9,1878 



,1871 



Aug. 17, 1871 



Sept. 2,1871 



Received from — 



T. H. Bean . . . . 

 F. S. Smitli ... - 

 IT. S. Fish Com. 

 ..-.do 



U. S. Fish Com. 

 F. H. Bradley. . 



P<05 

 to fj 



Dry. 



Ale. 



Ale. 

 Ale. 

 Ale. 

 Ale. 

 Ale. 

 Ale. 

 Ale. 



XII.— AXTHUEIDiE . 



Body elongate, cylindrical; mouth suctorial; legs ambulatory and pre- 

 hensile, the first pair enlarged; first pair of pleopods thickened and 

 crustaceous, protecting the following pairs ; uropods articulated at the 

 sides of the last segment, standing in a more or less vertical position and 

 forming with the telson a sort of cup or flower at the end of the body. 



