COPEPODS OF THE "WOODS HOLE REGION 499 



Color. — Body a clear opaque white when alive, on account of the 

 presence inside the body of numerous small spherical masses of 

 mesenchyme. The head is pink, the region around the digestive 

 canal and the spaces between the mesenchyme masses are translucent. 

 The canal itself and the pockets it sends out laterally are brownish or 

 reddish. The eggs are at first white but become pink or red upon 

 ripening. 



Female. — Head trapezoidal, wider behind than in front, one-half 

 longer than wide, the front margin evenly rounded, the carapace 

 divided dorsally by a median longitudinal line. In profile the head 

 slopes upward and backward and is distinctly gibbous behind, with 

 a soft horn or barb at each postero-lateral corner. First two seg- 

 ments free bearing the swimming legs ; second segment considerably 

 wider than the first, its anterior lateral corners produced forward 

 into small knobs. Last three segments fused, with an indistinct 

 groove across the center, a pair of long processes on the ventral sur- 

 face of the third segment, and a shorter pair at the posterior corners 

 of the fifth segment. Just in front of the genital segment on the 

 midline of the ventral surface is a small knob; the genital segment 

 is thick, somewhat flattened, and divided longitudinally by a ventral 

 transverse groove; there are no processes or prolongations on this 

 segment in these American specimens. 



First antennae with a fleshy, triangular basal segment and one or 

 two subspherical distal segments; second antennae enormous sickle- 

 shaped claws. Mandibles falcate with exceptionally large teeth; 

 maxillae with a papillate palp and a fringe of large teeth ; terminal 

 claw of maxilliped toothed on its inner margin. Each swimming 

 leg consists of a laminate basal segment and two rami; on the first 

 legs these rami are very small and more or less fused with the basal 

 segment, on the second legs they are long and well separated. Total 

 length, 7-12 mm. Egg strings, 12-14 mm. 



Male. — Head separated dorsally from, but fused ventrally with^ 

 the first segment, very much larger than the rest of the body and 

 considerably inflated dorsally. Trunk more or less distinctly seg- 

 mented, especially toward the tip; caudal rami conical, enlarged at 

 the base and acuminate at the tip. First antennae slender and 

 3-segmented; second antennae made up of a single segment with a 

 very stout apical claw; mouth parts similar to those of the female. 

 Each leg consists of a single lamina tipped with a short spine, with 

 another spine on the outer margin nearer the tip ; on the inner 

 margin at the base is a well-defined lobe with an apical spine. Total 

 length, 0.4-0.55 mm. 



Rernarhs. — ^Within the present area this species is apparently con- 

 fined to the silver hake, or whiting, and almost every fish yields 



