678 Brady and Noeman — Monograph of the Marine and FresMvater Ostracoda 



Shell seen from the side nearly circular, the infero-posteal corner produced into 

 a large conical process, ventral and dorsal margins nearly equally semicircular ; 

 anterior margin widely and regularly rounded, and circularly uniting with ventral 

 and dorsal margins ; surface very rugose, with concentric greatly elevated carina 

 enclosing a deep hollow in the centre of the valve; from the exterior of the carina 

 numerous radiating ribs pass on all sides to the margin ; the interstices of these 

 ribs and the central portion of the shell are sculptured with circular pittings. 

 Seen from above, the form is very irregular, but upon the whole slightly 

 cuneiform ; greatest width jjosterior, at which extremity it is abruptly truncate 

 and in the centre of the truncation the posterior conical process is seen projected; 

 from the truncated end the sides converge gradually at first, and then more 

 rapidly towards the anterior extremity, which is tolerably wide, and slightly 

 emarginate in the middle. End view with concave sides, dorsally arched, and 

 ventrally truncated. The valves are very much compressed in their centre. 

 Length, 1-2 mm.; height, 1 mm. The male is unknown. 



Antennules with second third and fourth joints sub-equal in length, the 

 second joint with one seta on front margin, the third with two on the front, and 

 three on hinder margin, the fourth with one long annulated seta which is not 

 ciliated or filiferous, fifth joint with three long annulated setae and some shorter 

 setae, at the distal extremity of hinder margin. Antennules bearing nine swim- 

 ming setae on the main branch, secondary branch rudimentary, consisting only of 

 a little nodulous process carrying one short seta. Mandibular palp strongly 

 unguiculate ; mandible itself without any masticating process ; first joint of palp 

 without masticating spines or laminar appendage but with two or three small 

 cilia on the hinder margin ; second joint curved, broad and strong, the length 

 not twice the breadth ; fourth joint extremely short ; each of the last three joints 

 bearing a strong curved unguis, the three ungues being close together, and the 

 distal longer than the preceding ; the joints are wholly devoid of setae, spines, or 

 cilia. The first maxillae (fig. 18) bear two or three lateral ciliated lobes, the pen- 

 ultimate joints bears a long spiniform ciliated seta on each side, and the last which 

 is about three times as broad as long, has its extremity furnished with five short 

 stout cuneiform spines, which are ciliated on the edges quite to the base, and 

 spread like the fingers of a hand. The second maxillae consist of a two-jointed 

 member bearing at the extremity seven or eight setae, but entirely devoid of 

 teeth or other structures of allied character ; a semicircular seta-edged vibratory 

 lamina is present. Caudal laminae with six ungues, which rapidly increase in 

 length, the last being produced and greatly longer than the preceding. 



Habitat— St Magnus Bay, Shetland, 30-60 fathoms, 1867; off Valentia, 

 Ireland, 1870 (A. M. N.). 



Distribution. — Off Capri, Bay of Naples, 1887 (A. M. N.). Messina and Syracuse 

 in 10-20 fathoms (G. O. Sars). 



