146 Prof. T. Rupert Jones — Fossil Ostracoda, Colorado. 



loses much of its brownness ; but some of the silica still retains a 

 brown tint. 



1. Mbtacypris Forbesii, Jones. Plate IV. Figs, la, 16, lc. 

 M. Forbesii, Jones, Quart. Journ. Geol. Soc, vol. xli. 1885, p. 345, pi. 8, 

 figs. 11-16 (including var. verrucosa); M. Forbesii, Jones, in Bullet. U.S. Geol. 

 Surv. February (?), 1886. 



Comparing our Figs, la, 16, lc, of the American Metacypris with 

 figs. 13 and 15 of plate 8 referred to above, we see no special 

 difference except that the antero-dorsal (nuchal) constriction is 

 stronger in the former two figures, and the valves are rather more 

 swollen in their posterior moiety. 1 The siliceous specimens figured 

 do not show the ornament seen in their English representatives ; but 

 some that have been beaten out (not separated by acid) show the 

 characteristic ornament, as stated above. Not rare. 



For the proportions of this and the other species, see the Table at 

 the end. 



2. Metacypris Bbadyi, sp. nov. PI. IV. Figs. 2a, 26, 2c. 

 If. Forbesii [var.], Jones, in Bullet. U.S. Geol. Survey, February (?), 1886. 



" This is even longer in proportion than our most oblong form," 

 such as fig. 11, pi. 8, Q.J.G.S. vol. xli. ; and the constriction is very 

 strong, being deep, curving forward, and reaching quite across the 

 valve. 2 The posterior moiety of each valve is relatively less swollen 

 than in Jf. Forbesii; but the convexity of the anterior portion is 

 more pronounced, and more markedly defined by the transverse 

 sulcus ; and, owing to the curve of the furrow, the hinder portion 

 has an almost round convexity. A pimple on the centre of this 

 part, and some few elsewhere, show an analogy to the warty con- 

 dition of M. Forbesii, var. verrucosa, op. cit. pi. 8, figs. 12 and 15. 

 Not rare. 



I propose to name this, as a distinct species, after my friend Dr. 

 G. S. Brady, F.R.S., who first recognized the genus Metacypris (oj). 

 cit. p. 311). 



3. Metacypris Whitei, sp. nov. PI. IV. Figs. 3a, 36, 3c. 

 Metacypris, sp. Jones, in Bullet. U.S. Geol. Survey, February (?), 1886. 



" This form is narrow [relatively], oblong, and compressed ; and 

 bears a distant resemblance to ' Gypris (?) conculcata,' Jones, Quart. 

 Journ. Geol. Soc, vol. xvi. 1860, p. 266, pi. 16, figs. 3a and 36" 

 (3c, young?). Valves oblong, nearly straight above and below, 

 almost equally rounded at the ends ; compressed in front, thicker 

 behind. Impressed at the anterior third with a shallow sulcus, and 

 with a faint hollow near the anterior hinge. Edge-view narrow- 

 ovate, sharp in front, obtuse behind, and somewhat undulate at the 

 sides by reason of the slight depressions. Not rare. 



1 Some of the English specimens are more constricted than shown in the figures 

 and descriptions, op. cit. p. 345. 



2 The transverse sulcus impressed on or near the mid-dorsal region of each valve 

 is characteristic also of Limnicy there and occurs in some other recent Ostracods of 

 estuarine and freshwater habitats, namely, Cyprideis (Cytkeridea), and one Cypris 

 (C gibba, Bamdohr). 



