the Pakeozoic Dlvalved Entoniostraca. 213 



The other known Silurian Cytherca are : — 



Cythere Bailyana, J. & H. \ 



Jukesi'ana, J. & H. I From the Caracloc beds of 



Ilarknessianay J. & H. / Kildare &c., Ann. N. II. scr.4. 



Wr{ghi!ana, J. & H. vol. ii. pp. 54-62 (1868). 



Aldensis, M'Coy. ] 



? siliqua, Jones. From the Trenton Limestone of 



Canada, described as a Cytheroj^sis (Ann. N. H. ser. 3. vol. i. 

 p. 249, pi. 10. %. 6). 



Other so-called Cyfltene and Cytherince from Silurian rocks, 

 such as C. suMcevi's, Shumard, C. alafa, De Verneuil, C. sub- 

 recta, Geinitz (not Portlock), and C. cylindrica, Hall, belong- 

 probably to Leperdltia' and cognate genera. 



Bairdia P/till/jjsiana, sp. nov. PL XIV. figs. 7 a, h, c. 



Carapace subfalciform, with obliquely rounded, tapering, 

 almost equal ends, highly arched back, and faintly incurved 

 ventral border. The left valve very much overlaps the other, 

 especially on the dorsal edge. Profile acute-oval. 



This almost symmetrical Bairdia (in lateral aspect not un- 

 like the recent British B. fidva, described by Mr. G. S. Brady 

 in his " Monograph of the Recent British Ostracoda," Trans. 

 Linn. Soc. vol. xxvi. p. 474, pi. 28. fig. 21) is from the Wen- 

 lock Limestone of Croft's Quarry, near West ]\Ialvern, but is 

 not common ; and we name it after Prof. John Phillips, F.R.S., 

 who years ago shed much light on the geology and fossils of 

 the Malvern district. 



A very similar form to this (and probably identical) occurs 

 in a piece of a di-ifted Scandinavian block of Silurian Limestone 

 from near Breslau. 



The other Silurian Bairdia are — Bairdia 2Iurchisonia7ia, 

 B. GriJfifJiiana, and B. Salteriana, from the Caradoc beds of 

 Kildare, described by us in Ann. N. H. ser. 4. vol. ii. p. 58 

 (1868), and Bairdia 2>^'otracta, Eichwald, Leth. Rossica, livr. 

 vii. (1866,) p. 1338, pi. 52. fig. 19, from the Coral-limestone 

 (Upper-Silurian) of Kamenetz-Podolsk. 



Thlipsura*, gen. nov. 



A Cytheroid carapace, indented on its anterior third by a 

 variable and evanescent pit, and posteriorly by a deeper and 

 permanent depression, characterizes the Silurian specimens 

 which we have to place by themselves in this new generic group. 



* So called in allusion to the compression of the posterior extremity : 

 ^XtA/^tr, pressure, and ovpa, tail. 



