﻿JURASSIC AND TRIASSIC BRACHIOPODA. 



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but, as any one will at a glance perceive, the shells referred to belong to two distinct 

 species. It is difficult, therefore, to know what shell Schlotheim had in view, and as a 

 well-known species, occurring in the White Jura of Germany, was subsequently 

 described by Zieten under the same name, I think if will be preferable to adopt Zieten's 

 species and figures for the shell under description. It must, however, be noted that 

 many specimens of this species bear so great a general resemblance to Ter. perovalis 

 (Sow.) from the Inferior Oolite of England and France, that it is very difficult, if even 

 possible, to distinguish them. In 1862, I figured and referred a specimen from 

 Braambury Hill to Sowerby's species, and am not yet satisfied, notwithstanding the 

 difference in geological horizon, that the view I then took was not the correct one. 

 Some time after, I received from Dr. Sandberger some German specimens and internal 

 casts labelled T. bisuffarcinata, Zieten, from the Korallen-Kalk of Muggendorf. These 

 I compared with a large number of specimens from Braambury Hill, Sutherlandshire, 

 procured by Mr. Judd from the Coralline Oolite (or Zone of Awn. perarmatus, Lower 

 Calcareous Grit) : I found them exactly similar, and think, therefore, it will be best to 

 retain Zieten's name, although it is very evident that more than one form has been referred 

 to this species by other Paleontologists. T. bisuffarcinata is very variable in shape, and 

 (like T. perovalis) more or less elongated and deeply biplicated. These characteristics 

 are often absent in adult specimens of Sowerby's species. It does not appear to have 

 attained the dimensions of T. perovalis. I do not give references to doubtful figures. 



86. Terebratula insignis, Schilbler. Sup., PI. XV, fig. 7. 



Terebkatula insignis, Schiibler. Zeiten. Verst. Wurt, pi. xi, fig. 1, 1832. 



Terebratula insignis is a large shell occurring abundantly in the Coralline Oolite of 

 Germany, Prance, and England. It varies considerably in shape and dimensions. At 

 Nattheim it sometimes exceeds three inches in length, while in other places it is much 

 dwarfed. 



At p. 608 of his 'Die Jura-Pormation ' (1857) Dr. Oppel proposes to distinguish the 

 shell I figured and described at p. 47 of my Monograph by the varietal designation of 

 Maltonensis. This view has been likewise taken by Mr. Walker and some other palaeonto- 

 logists. Mr. de Loriol, on the contrary, observes at p. 233 of his great work on the 

 1 Paleontologie des Etages superieurs du Boulonnais,' that he has seen and found every 

 passage of form connecting the Malton variety with the large oval specimens figured by 

 Zieten. He has also seen specimens from Nattheim showing so clearly every variation 

 in form that he could not distinguish where the typical shape terminated or where the 



