712 Brady and Norman — Monograph of the Marine and Freshwater Ostracoda 



Genus Cytherella, Bosquet. 



Shell usually elongated and compressed, very thick and hard ; valves very 

 unequal, the right much the larger and overlapping the left through the w^hole 

 circumference ; surface very variable in sculpture, usually smooth or punctate, 

 but sometimes rugose. Muscle spots (PI. lxvi., fig. 9) numerous, forming an oval 

 patch near the centre of the valves, spots elongated or linear, and arranged in two 

 rows, the axes of the spots convergent, so as to form a pinnate pattei'n. 

 Antennules very large and stout, geniculated at the junction of the first and second 

 joints ; first two joints massive, and bearing marginal tufts of setae, the remaining 

 joints gradually decreasing in breadth, and setose on the margins. Antennse 

 composed of a stout, bi-articulate basal portion and two branches ; outer branch 

 composed of two joints; inner longer and three- join ted ; both branches furnished 

 profusely with long, stout setae. 



"Mandibles very weak and strongly bent towards the apex; biting edge 

 obliquely truncated, and furnished with a pectinate series of slender teeth" (Gr. 0. 

 Sars) ; palp two- jointed, large, cylindrical, and only slightly curved, beset along 

 the greater part of its length with a series of extremely long, slender, closely- 

 packed, and backward -cui'ved setae (40—50 in number), and bearing near the base 

 a small branchial appendage. First pair of maxillae composed of three setiferous 

 biting lobes and a very large two-jointed palp, which is armed, like that of the 

 mandible, with numerous long setae ; inner margin of the basal portion divided 

 into three arcuate lobes, each of which bears four rather rigid and short backward- 

 pointing setae ; the last joint of the palp ends in two setae and a club-shaped sensory 

 appendage; there is also a very large branchial lamina with numerous, very 

 long, marginal setae. Second pair of maxillae very small, composed of an ovate 

 lamina, which bears a few marginal tooth-like setae, and a narrow ovate branchial 

 plate, furnished with about twenty-two setae, the last two setae of different 

 structure from the rest and non-plumose ; in the male the limb is much more 

 largely developed, and forms a powerful prehensile organ, the basal point of 

 which is hatchet-shaped. Third pair of maxillae, in the female, " rudimentary, 

 and forming a simple setiferous lobe " (Sars), bearing an almost semicircular 

 branchial plate with about fourteen setae ; in the male, prehensile, and not unlike 

 the preceding pair. Caudal rami small, narrow, fringed with setae, which gradu- 

 ally increase in length from the first on the ventral margin to the last, which is 

 situated behind the middle of the dorsal margin, is stouter than the rest, strongly 

 curved and directed forwards over the dorsum. Copulatory organs of the male 

 very large, curved, subcylindrical. Abdomen divided into numerous segments, 

 which are bordered more or less completely by narrow chitinous bands. 



