COPEPODS OF THE WOODS HOLE REGION 507 



Female. — Body short and stout; head defiexed at right angles to 

 the body axis, somewhat flattened dorso-ventrally, and enlarged 

 where it joins the thorax. First segment very short and bearing 

 only the first legs on its ventral surface; to each nide of the second, 

 third, and fourth segments is attached a short, clavate, fleshy process, 

 the first two pairs extending ventrally, the third pair outward and 

 backward. The genital segment is about the same length and width, 

 the single abdominal segment is globular and without caudal rami. 

 On the dorsal surface of the second segment is a flattened ridge along 

 the midline, which grows forward against the first segment and 

 pushes the latter first into an oblique position, and eventually into 

 a vertical position. In the youngest specimens obtained the head 

 is but little defiexed, but in all the maturer specimens it is turned 

 downward at a right angle. There are similar pads along the dorsal 

 midline of the third and fourth segments, and they also push for- 

 ward against the segment in front of them. The dorsal portion of 

 the grooves between the segments is thus carried considerably in 

 front of the ventral portion. 



The first antennae are small, fleshy, and unsegmented; the second 

 antenna is large and stout; its terminal claw is curved but little, is 

 very bluntly rounded, and is armed on its concave margin with a 

 short process. The mandible is almost straight, rather bluntly 

 pointed, and has no fringe of teeth along either margin. The ter- 

 minal segment of the maxilla is spinelike and has three or four teeth 

 on its inner margin; the palp is lacking. The maxilliped is 2-seg- 

 mented, the distal segment ending in a rounded denticulate knob and 

 a short and stout claw. Each swimming leg consists of a swollen 

 and more or less cylindrical basipod tipped with two minute, 1-seg- 

 mented rami. Ovisacs cylindrical and longer than the urosome. 

 Total length, 3,5-4 mm. Greatest width, 2.25 mm. 



Male. — Head fused with the first segment and ventrally with the 

 second segment, but the latter is separated on the dorsal surface by 

 a well-defined groove. The carapace also covers the first segment 

 but does not cover the second, and forms a knoblike angle on each 

 side 'opposite the mouth. The trunk is distinctly segmented and 

 about the same diameter throughout; the caudal rami are stout and 

 conical, more or less fused at the base, and each is tipped with a 

 minute cilium. The first antennae are slender and indistinctly 3-seg- 

 mented, armed with small spines ; the second antenna is 3-segmented, 

 with a curved apical claw and a stout accessory claw on the outer 

 margin of the distal segment. The mouth parts are similar to those 

 of the female; the swimming legs are biramose, each made up of a 

 laminate basipod, armed with a stout seta at its outer distal corner, 

 and two flattened rami. The exopods are ovate and armed apically 



