370 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



straight spine below it. In the first pair of legs the carpus is short and 

 triangular, the ischiuin and merus bear on their upper margin a row of 

 long slender plumose hairs. In the second and third pairs of legs these 

 hairs are also found, and the carpus is longer. The fourth pair of legs 

 are robust, the following pairs more slender to the seventh. All are well 

 provided with slender hairs, with a few stouter ones intermixed. 



The anterior segments of the pleon are consolidated into a single piece 

 somewhat resembling the last thoracic segment, but marked at the 

 sides by depressed lines, indicating sutures, as shown in pi. IX, fig. 53. 

 At the sides this segment is broadly rounded and projects much below 

 the seventh thoracic when the animal is contracted. The large terminal 

 segment has a similar lobe in front of the bases of the uropods. At the 

 insertion of the uropods the segment is considerably contracted laterally, 

 but is rounded and strongly margined behind. Its anterior lobe, all the 

 thoracic segments, and the head are also margined by an elevation run- 

 ning completely around the animal except where it is interrupted by 

 the uropods. The uropods extend nearly to the tip of the telson, and 

 consist on each side of a basal segment continued backward into a nar- 

 row oval plate with entire margins, flattened below, where a similarly- 

 shaped ramus is articulated near its base, the two shutting together like 

 the blades of a pair of scissors. The articulated plate bears four more or 

 less acute serrations on its exterior margin, whence the specific name. 

 The pleopods are ciliated, and the second pair (pi. IX, fig. 54 c) bears, in 

 the male, on the inner lamella, a slender curved stylet, longer than the 

 lamella, and articulated near its base. 



Length about 8 rain , breadth 4". The color, as usual in shore species, 

 is variable ; some are of a uniform slaty gray, many are marked on the 

 dorsal surface with a whitish, cream color, or rosaceous patch, bordered 

 more or less with dark or black. This patch has commonly a longitud- 

 inal direction, and is usually symmetrical, and may be broad or much 

 narrowed in the middle. On the dark or barnacle-covered rocks, where 

 these animals are often found, the colors are evidently protective, but 

 they are imperfectly preserved in alcohol. 



This species was described by Say, who "found these animals very 

 numerous on the beach of Saint Catherine's Island, Georgia, concealing 

 themselves under the raised bark, and in the deserted holes of the 

 Teredo, &c., of such dead trees as are periodically immersed." He also 

 gives East Florida as a locality, and there are specimens in the Yale 

 Museum from Florida ! It extends as far north as Provincetown, Mass. ! 

 near the extremity of Cape Cod. It is common on the southern shore 

 of New England!, and is usually found among alga3 or rocks. 



