388 Prof. T. Rupert Jones — On some Fossil Estlierice. 



wrinkles; in its straight back and feeble lines of growth it is like 

 fig. 5, pi. 2, but its postero-ventral curve is much fuller. The little 

 Fig. 6 matches fig. 14, pi. 2, the small Ehastic variety Brodienna, 

 but it has not quite so prominent an umbo, and is rather squarer in 

 outline. 



Fig. 7, labelled " E. Albertii (Voltz), Baden," is in a hard micaceous 

 shale, light-grey and purplish ; it is not much larger than fig. 9, 

 pi. 2, and differs only triflingly in outline, being rather fuller in the 

 an tero- ventral curve, less angular in front of the umbo, and having 

 slightly stronger concentric ridges. With its relatively small size 

 and oblong shape Fig. 7 (4^ by 3 mm.) comes in as a large form of 

 var. Brodieana. It is from the upper red clay of the Gres bigarre, 

 at Durlach, Baden. 



In a piece of thin, dull-red shale from the Pfinzthal, Baden, is a 

 shining, compressed cast of another specimen, labelled " E. Albertii 

 (Voltz)," similar to Fig. 7, and measures 4 by 3 mm. 



On one of the bed-planes of an inch-thick mudstone, dark-grey, 

 hard, fine-grained, and slightly micaceous, from the Lettenkohle of 

 Wiirzburg, Bavaria, are numbers of a small form of " Estheria 

 minuta " (about 4 by 2^ mm.) crowded together. On the other bed- 

 plane is a group of Pidlastra-Wke bivalves in casts and impressions. 

 Fig. 8, labelled " JE. laxitexta, Sandberger, from the Estheria-bed 

 of the Lower Keuper, at Windsheim, Middle Franconia," is a fine 

 large Estheria with shape and ornament like those of E. minuta, 

 Fig. 8a is comparable with fig. 5, pi. 2, of the " Monogr. Foss. 

 Esth." 1863, though somewhat larger, and having a fuller curve 

 at the antero-ventral margin. The reticulate sculpture of the 

 concentric interspaces is essentially the same as that in figs. 3 & 7 

 of the pi. 2 referred to, so that I cannot find good ground for 

 following Prof. Dr. Fr. von Sandberger in separating this form from 

 E. minuta. He tells me in a letter (May 8th, 1890), that he 

 " separated E. laxitexta, which occurs high above the stratum with 

 E. minuta, from that species on account of the difference in the 

 sculpture ; that he has not described nor figured it ; and that its 

 relatively larger size was not the reason of his separating it from 

 E. minuta." Certainly the slight difference in size and contour is not 

 sufficient for a specific distinction ; and the sculpture of the selected 

 specimen shows no difference. 



E. laxitexta was mentioned by Dr. von Sandberger in the 

 " Verhandlungen d. k. k. geol. Reichsantalt " (Wien), No. 16, 1871, 

 p. 323, in a note on the Estheria-bed of the Keuper in South France ; 

 but, by some mistake, it is there stated to have been described, from 

 English specimens, by me, as a variety of E. minuta, occurring 

 exclusively in the Lettenkohle. 



Some of the specimens before me are numerous and relatively well 

 preserved on the bed-planes of a greenish shale, rather hard and 

 slightly micaceous, from near Bayreuth (Upper Franconia) and in 

 the Steigerwald, like (von Sandberger states) the Estheria-bed of the 

 Keuper in Swabia and in the Department Gard in South France. 

 Others lie less regularly in a grey, harder, and more solid mudstone 



