TRAPEZIUM. 149 



strong concentric liiniell*. Tlic oriKunontation is indisliiicl on llic ]iai't alxjvc the 

 rounded ridge. Margin of valve crenulate. 



MeasiU'i'iHcnts : 



(1) (2) 



Length . 15-5 . 14 

 Height . 12 II 



Thickness . 10 . 1() 



(1 — 4) Lower GreeusanJ, Upwaro. 



.[(ji II 'dies. — Keeping coniparetl this species with (JanlUn iiajcoiiiirusis, d"Oi-l)igiiy, 

 to which it shows some resemblance in general form. Bnt the faint radial ribs 

 and strong concentric lamella', as Avell as tlie cliaraeter of the hinge, so far as it 

 can be made out, seem to connect this species with Tntjicxiniii, ratlier tlian witli 

 Gardita. 



Tijpe. — In the Sedgwick Museum. 



Distr'ibutiuii. — Lower Greensand, Upwai-e. 



Trai'KZIUM ? sp. riate XXIII, fig. IG. 



1883. Cypkicakdia striata, W. KcepiiKj. Fuss., utc, Nuoc. Upware aud Urickliill. 



p. 119. 



An imperfect left valve from the Lower (Jreensand of Upware, in the Sedgwick 

 Museum, was identified by W. Keeping with Gi/pricardin driula (Geinitz) ' from 

 the Ceiioniauian of Saxony. The ribs are fewer in nuiubei- than in the examples 

 of C. striata figured by Geinitz. 



Ti;Ari:zirM TUArE/.oin.vLi': {lu'iinrr), 1811. Tlate XXIII, figs. 17— H». 



18-41. Crassatella TitAriizoiDALis, F. A. Itiiiiur. Die Versteiu. d. uorJ-deiitsL-h. 



Kreidcyelj., p. 74. pi. i.\, 



? 1847. — — -1- d'Aicluuc. Mi'm. Soc. i,'L'ol. du Franco, 



sur. 2, vi)l. ii. p. 302. 

 1850. Cyi'KINA — if B. Geinitz. Das Quadursaudst. odor 



Kn-idogcb. iu Dcutsoli- 

 laud, p. 168 (/ic(Wim). 

 1854. C'ypRiCAKDiA - A. d'Ovbiginj. Prodr. de Pal., vol. ii. p. 240. 



1 • Char. d. Schicht. u. Potrof. des siichs. Kreide-eb.,' pt. 2 (1840). p. 52, pi. x, fife'. 3. Modiol,, 

 cardiloiih->>, (ieiuitz, 'Das ElWliali^'elx iu Sa*;l)seu ' (• Palajoutoyrai.hica,' vol. xx, pt. 1. 1873), p. 218. 

 pi. xlviii. fij,'s. 11—13 ; pi. .\iix, tigs. 11», 20. 



