RECENT BRITISH OSTRACODA. 



379 



joint. It occupies a position similar to that of the biarticulate seta which is uniformly 

 present in the freshwater Cypridae ; and I have noticed that in some of these (e. g. Cypri- 

 dopsis vidua) the extremity of the seta forms a sac somewhat similar, but not so largely 

 developed. 



Genus 4. Notodromas, Lilljehorg. 

 {Cyprois, Zenker; Newnhamia, King.) 



Carapace of very different shape in the male and female. Two eyes. Antennae similar 

 to those of Cypris ; the superior composed of seven, the inferior of six joints. Setae of 

 the inferior antennae reaching beyond the apex of the terminal claws. Second pair 

 of jaws without a branchial appendage, pediform in the male. Abdominal rami long 

 and slender. Mucus-gland of the male large, beset with very numerous closely set 

 whorls of stout rigid setae. Copulative organs of very complex structure. 



The genera Cyprois (Zenker) and NeiDnhamia (King) seem to be identical, or nearly 

 so, with Notodromas (Lilljeborg). The torose, tuberculated condition of the valves of 

 Newnhamia cannot be considered as supplying a distinctive generic character ; while 

 the general contour of the carapace and the " boat-like plate " of the ventral surface are 

 remarkably in accordance with the English species N. monachus. A more important 

 difference (if borne out by further observation) is the presence in Newnha/mia of a 

 branchial appendage to the second pair of jaw-feet. Mr. King states that this is present 

 in all the Australian Cypridae, though he does not specially mention it in his definition 

 of the genus or species of Newnhamia. But from the more general statement, we are 

 left to infer the presence of this appendage. Mr. King describes Neionhamia as pos- 

 sessing also transparent ocular tubercles. 



Notodromas monachus (Miiller). (Plate XXIII. figs. 1-9, and Plate XXXVII. fig. 3.) 



Cypris monacha, Miiller, Entomostraca (1785), p. 60, tab. v. figs. 6-8; Baird, Natural History of 



British Entomostraca, p. 153, tab. xviii. fig. 6. 

 Monoculus monachus, Jurine, Hist, des Monocles, p. 173, pi. xviii. figs. 13, 14. 



Notodromas monachus, Lilljeborg, De Crustaceis ex ord. tribus, p. 95, tab. viii. figs. 1-15, tab. xii. 

 figs. 1, 2, tab. XXV. fig. 16. 



Male. — Carapace obliquely subquadrangular, greatest height equal to two-thirds of the 

 length, situated in the middle. Anterior margin broad, rounded at the angles, and 

 expanded into a flattened lamina or flange. Ventral margin straight for about two-thirds 

 of its length, then bending upwards at an obtuse angle. Dorsal margin arched, almost 

 angular in the middle, whence it slopes steeply to the anterior border, and with a bold 

 curve towards the posterior extremity, joining the ventral margin at an acute angle. 

 Seen from above, the carapace is ovate, pointed in front, and rounded behind ; the greatest 

 breadth in the middle. The ventral surface is bounded by two conspicuous, elevated, 

 arcuate ridges (figs. 3, 6), one on each valve, which together enclose a flattened lozenge- 

 shaped area. Parallel to the contact margin of each valve runs another straight but 

 much less conspicuous ridge, which, towards the front, curves outward, and joins the 

 external ridge at an acute angle, the union of the two forming a slight elevation (fig. 6 a), 



3 F 2 



