658 Beady and Norman — Monograph of the Marine and Freshwater Ostracoda 



3. Philomed.es Lilljeborgii (Gr. 0. Sars). 

 (PI. LI., figs. 4-6; PI. Lii., figs. 3, 4.) 



1865. Brady cinetus Lilljeborgii, Sars, G. 0., " Oversigt af Norges marine Ostra- 



coder," Vid.-Selsk. Forhand, p. 112 (separate 

 copy). 



Shell of ? roundedly-quadrangular, greatest height central, equal to nearly 

 three-fourths of the length ; ventral margin well, but not boldly, arched ; dorsal 

 margin nearly straight in the central portion, in front boldly arching to the 

 rostrate extremity ; hinder margin abruptly, and somewhat obliquely truncate, 

 the infero-posteal corner produced into a much compressed and backward-directed 

 point, anterior margin formed by the continuous sweep of the dorsal, until 

 abruptly cut off by the almost horizontal face of the rostrate process, which is 

 broad; antennal sinus inferior, moderately open, well-rounded at its junction with 

 the ventral margin. Seen from above ovate, with a mucro behind, caused by the 

 infero-posteal produced angle; greatest width central, equal to half the length, 

 sides evenly arched. Surface of valves everywhere finely punctate, not setose, 

 though the ventral margin is fringed with fine cilia, which attain much greater 

 length on the margins of the antennal sinus, and front of the rostrate process. 

 Length, 2"6 mm.; height, 1*8 mm. 



The male differs from ? in a similar manner to that of P. hrenda, the form 

 being more oblong (PI. li., fig. 4), ventral and dorsal margins nearly straight 

 centrally, the latter slightly emarginate ; the inferior portion of the rostrate 

 process is, as it were, cut off, the horizontal front being thrown back as far as the 

 bottom of the sinus, which is thus widely open, and affords ample scope for the 

 play of the large antennules ; greatest height, half the length. There is a 

 projection at the infero-posteal corner similar to that of the female, but not so 

 strongly pronounced. 



In ? the antennules have the second joint about equal in length to the rest 

 of the limb. The appendage of the antennae (fig. 6) has one seta on the first 

 joint, and three (of which that nearest the base is long and plumose), besides 

 the terminal hook-formed seta on the second. The forked process and masticatory 

 spines of this sex are as in P. brenda. Vermiform last limbs with few, 10—12, 

 spines. The caudal laminae have 9—11 ungues, which gradually increase in length 

 and size, and are strongly denticulate on the edge. 



In the 3 the antennae have the third joint of the swimming branch, as usual, 

 longer than the second, and there are eleven natatory setae, the two distal of 



