56 rT^ETATEOUR LAMETJJrJTi AXCTTTA. 



smallev tliau clsewluTt', but tlie luiddlo rows of spines are here often relatively 

 larger. 



Measurements : 



(I) (2) (-.i) (4) (5) (0) (7) (S) (0-» (10) (in 



LeiiKtli 10 Ti 1-") 11 10 10 10 8 0-:) Ki -Ji mm. 

 Heiglit 21 IS Ki ]2-r, 11 lo:) 11 In is r2\- „ 



(1 — 5) li. inncroruita zone, Norwich. 

 (0) „ „ Aldorluivy. 



(7) A. quadratus zone, East, Haruham. 



(8) B. mucronata zone, Clarendon. 

 (9—11) Chalk of Trimingham. 



Afjhiitles. — The form from the Lower Senonian of Touraine described and figured 

 as Lima r/ranulata by Dujardin, is regarded by Peron ' as belonging to another 

 species which he names Lima Meslei. Peron states that L. Meslei differs from L. 

 granulata in having more numerous ribs ornamented with fine granides of which 

 the middle row is not larger than the lateral rows ; further, the ribs disappear on 

 the anterior and postei'ior parts of the shell, and the ears are without ornamen- 

 tation. 



liiulnla scahrinila, Stoliczka," from the Arrialoor Group, is closely related to 

 Lima granulata, but owing to the imperfect preservation of the single valve on 

 which the species is founded, an exact comparison is not possible. The ornamen- 

 tation, however, seems to differ, since it apparently consists of small tubercles of 

 nearly equal size. It has been suggested by Holzapfel and Hennig that Lima 

 'pseuducard'uim, Reuss,' may be identical with L. granulata, but the ornamentation 

 on the ribs of that species appears to be unknown. 



Bemarks. — This species has been referred to Limea by Brauns, Zittel, and 

 Griepenkerl, l)ut later Avriters — Holzapfel, Hennig, and RaAni — retain it in the 

 genus Lima since they find no evidence of the existence of a taxodont hinge. 

 The specimens which I have seen do not show the hinge. 



The outline of the shell varies to some extent in L. granulata, deiJcndingmainl}^ 

 on the obliquity of the valves. The appearance of the ribs varies considerablj' and 

 is probably due chiefly to the state of preservation ; in the more perfect specimens 

 the terminations of the scale-like spines become erect, in otlici's flic s])ines are 

 in llie form of sloping scales, whilst in some cases tliey arc i'c|ircsciitc(l by 

 tubci'cles onlv. The iuinil)er of ribs also shows variation. 



'• ' L'Hist. du Terr, de Craie' (1888), p. 148, pi. i, figs. 21—24. 



2 ' Palffiont. Indica, Grot,. Faima S. India' (1871), vol. iii, p. 419, pi. xxx, fij,'. 8. 



s 'Die Vcrstein. der biilim. Krcideformat.' (1846), i)t. 2, p. 33, pi. xxxviii, figs. 2, 3; Geiuitz, 

 "Das Elbthalgeb. in Sachsen " (' Paloeontograpliica,' vol. xx, pt. 1, 1872), p. 204, pi. xlii, figs. 14, 1.5 : 

 see also Braiuis (1876), Fritsch (1877, 1883), Michael (1893), Leonhard (1897). 



