220 CRETACEOUS LAiMELLIBRANCHIA. 



1864. SoLEN DUPiNiANUs, F. J. Ficfii and G. Caiiipiche. Terr. Cret. Ste. Croix 



(Mati'r. Pal. Suisse, ser. 4), p. 29. 



1897. — — R. B. Neivtoii. Proc. Dorset Nat. Hist, aud Antiq. 



Field Club, vol. xviii, p. 93. 



Description. — Shell ulongate, more or le.ss oblong, slightly convex, coinpre.ssed 

 near the antero-dorsal margin, considerably inequilateral. Dorsal margin nearly 

 straight. Anterior end roimded, not so high as the posterior part of the shell. 

 Ventral niai'gin nearly straight and neai'ly pai'allel to the dtirsal margin, curving 

 upAvards anteriorly. Posterior margin convex, forming a rounded angle with the 

 ventral margin. Umbones small, inconspicuous, situated at less than a third of 

 the length of the shell from the anterior margin. 



Ornamentation consists of small concentric ridges; in some cases the ridges 



cut the ])osterior part of the ventral margin obliquely. A strong internal rib 



extends from the umbo veutrally, l)ut does not reach the venti-al mai'giii. 



Measurements : 



W (2) (a) 



Length . . 31 . 29 . 2G mm. 



Height . . 10 . 10 . 9 „ 



(1—3) Gault, Black Veu. 



AQiniticfy. — The occurrence of this species in the Gault of England has been 

 recorded by De Ranee and R. B. Newton — by the former from Black Ven, and by 

 the latter from Okeford Fitzpaine. Although the example figured by d'Orbigny 

 is imperfect, consisting of the posterior part of a left valve only, yet the English 

 specimens agree sufficiently closely with d'Orbigny's figure to make it probable 

 that they have been correctly identified with fj. Diqnnianus. In most of the 

 English examples, however, the posterior margin is more convex and the ])ostero- 

 dorsal angle more rounded than in d'Orbigny's figure; but in a few s^jeciniens, 

 which have been slightly crushed, these differences are not noticeable. 



The species which resemble L. JJiqnniaiiKS are A/. ro)u-riitrisfriiihi!> (Miiller'), 

 L. Petersl (Reuss"), /;. fnnicuhila (Reuss'^), L. ]\liire<tna (d'Orbigny') and /,. liimita 

 (Stoliczka"'). 



Ti/pc. — From the Albian of Ervy (Aube). 



JJlstrlhution. — Lower Gault of Black Yen antl Okeford Fitz|)aine. L'lqier Green- 

 sand of Devizes. Recorded by Jukes-Browne from the Gault of the Isle of Wight. 



' ' Jalirli. d. k. preussiseh. i,'e(il. Laudesanst. i'iir 1887 ' (1888), p. 4ol, pi. xviii. fii,'. 5. 



' ' Kreidesc-bicht. i. d. Ostalpeu ' (1854), p. 145, pi. xxviii, fiy. lO. Zittel. "Die Bivalv. d. 

 Gosaugeb.,' I (1865), p. 5 [109], pi. i, fi;;-. 3. 



^ ' Die Versteiu. derbiibm. Kreidei'i)rinat.,' \t\. '1 (1846), p. 17, pi. xxxvi. fi,L;.s. 13, 16, 17. 



» 'Pal. Fraiu;. Terr. Crut.,' vol. iii (1845), p. 324, pi. eecl, figs. 8—10. Tins species bas beeu 

 recorded by Barrois from tbe Upper Greensand of Lulwortb and Devi/es ; I bavi; not seen any 

 examples from tbosu localities. 



"•> 'Palseout. Indica, Cret. Fauna S. India' (1870). p. 101, pi. i, tigs. 12, 13. 



