674 Brady and Norman — Monograph of the 3Iarine and Freshvater Ostracoda 



all over, and sculptured witli numerous riblets, two of these pass longitudinally 

 round the ventral portion ; another starting from the anterior extremity as its 

 base gradually approaches the dorsal margin which it nearly meets at 

 about two-thirds of its length; another longitudinal riblet is situated a little 

 above the centre, and passes backwards till it approaches the hinder extremity, 

 when it sweeps downwards and after forming two lobes unites with the ventral 

 riblets ; at the position of the two lobes just mentioned the valves attain their 

 maximum obesity, and beyond this they are suddenly depressed to the flattened 

 hinder extremity ; a little in fi'ont of the middle of the shell there is a nodulous 

 protuberance lying between the two uppermost riblets. Greatest height sub- 

 central, equal to nearly three-fourths of the length ; greatest width equal to only 

 half the height. Seen from above the form is cuneate, abruptly truncated behind, 

 with a slight central protuberance caused by the compressed hinder extremity, 

 which juts out beyond the point of maximum breadth of the valves ; from the 

 truncation the sides converge forwards, at first only gently, but at two-thirds the 

 length more suddenly, and meet at a slightly obtuse extremity in front. 

 The end view shows that when the valves are broadest they are nearly equally 

 so throughout their height. Length, 1*5 mm.; height, 1 ram. 



Female (?) Frontal tentacle very long and slender. Antennules (fig. 12) 

 five-jointed, geniculated at the end of the first joint, which is one-third longer 

 than the second ; second, third, and fom'th joints sub-equal in length, last minute ; 

 the second joint bears one seta on the outer margin ; the third one seta on each 

 margin at its base, a seta at the end of the upper, and two rather long annulated 

 setae at the end of the lower margin ; the foui'th two minute setse on the upper and 

 a large annulated seta on the lower margin at the extremity ; last joint with three 

 large annulated setse, and three of smaller size. 



The antennae (fig. 13) have the basal-joint pyriform, not so broad or large as 

 usual, the length greater than the breadth ; swimming-branch also rather more 

 slender than usual, nine-jointed, the first joint long and slender, second to eighth, 

 each with a swimming seta, last with five set^, the furthest minute, and the next 

 also short ; appendicular branch altogether absent. 



The palp of the mandible (fig. 14) is of very remarkable structure, consisting 

 of only two joints and a chela ; the mandible itself has a bifid masticating process. 

 The first joint of palp has on the lower margin two masticating spines 

 which are tuberculated on their edge, and two setse, one of which is in front of 

 and the other behind these spines ; a third seta is borne at the end of the outer 

 margin ; second joint of immensely strong build, the outer margin very boldly 

 arched, and bearing at its centre two small setje, and one small seta at the 

 inner- distal corner, otherwise the joint is naked; to its extremity is attached a 

 very large and strong chela, the outer member of which is the shorter, falcate, 



