44 TERTIARY ENTOMOSTRACA OE ENGLAND. 



anteriorly, and in being less strongly notched behind. Allied forms are known to 



us from several Jurassic strata. 



From the Belosepia-bed, Bracklesham. (British Museum.) 



Named after Professor Prestwich, D.C.L., F.R.S., who has so greatly advanced 



our knowledge of the Tertiary deposits. 



2. Cytherura clathrata, G. 0. Sars. Plate III, figs. 24 a, b. 



Cytheeuba clathrata, Q. O. Sars. Brady, Trans. Linn. Soc, vol. xxvi, 1868, 



p. 446, pi. xxix, figs. 43 — 46 ; B., C, and R., Monogr. 

 Post-Tert. Entom., 1874, p. 204, pi. xi, figs. 1—4; 

 Jones & Sherborn, Geol. Mag., 1887, p. 457. 



In this small and interesting form the oval carapace is somewhat sharper 

 behind than before, and more compressed in front than behind. It has the 

 surface ornamented with a strong median ridge, branching freely off towards the 

 margin. The main branches in our specimen keep their entirety, but Dr. G. S. 

 Brady figures individuals in which the branches lose themselves in a rough 

 general reticulation over the surface. 



From the Weybourn Crag of East Runton. Collected by Mr. Clement 

 Reid, F.G.S. (Museum Practical Geology.) 



XIX. CYTHEROPTERON, G. 0. Sars, 1865. 



G. S. Brady, Trans. Linn. Soc, vol. xxvi, 1868, p. 447. 



Brady, Crosskey and Robertson, Monogr. Post-Tert. Entom., 1874, p. 201. 



1. Cytheropteron triangulare (Reuss). Plate II, figs. 19 a, b, c. 



Cytheee teiangulabis, Reuss. Zeitschr. deutsch. geol. Ges., vol. vii, 1855, p. 279, 



pi. x, fig. 3. 



— — Jones. Monogr. Tert. Entom., 1857, p. 25, pi. vii, fig. 5. 



— tenuiceistata, Reuss. Sitzungsb. k. Akad. "Wiss. Wien, vol. lii, 1865, 



p. 467, pi. not numbered, fig. 12. 

 Cxtheeopteeon teiangulaee, Jones. Geol. Mag., 1870, p. 156. 



— — J. & S. Geol. Mag., 1887, p. 457, pi. xi, fig. 16. 



This well-marked form has already been well described, as well as several 

 allies, namely, Cytheropteron mucronalatum, Brady (' Challenger, &c.,' 1880, p. 140, 

 pi. xxxiii, fig. 8) ; C. fenestration, Brady (Ibid., p. 139, pi. xxxiv, fig. 6), both 



