142 FOREIGN OOLITIC PSEUDODIADEMAS. 



and sharply crenulated ; primary tubercles of both areas nearly of the same size, large, 

 round, and prominent ; areolas narrow, and encircled with small, round, spaced -out 

 granules ; poriferous zones narrow ; pores bigeminal in the upper part of the zones ; 

 miliary zone of moderate width, with a few granules at the equator, but naked in the 

 upper part of the area ; mouth opening less than one half the diameter of the test ; 

 peristome decagonal, divided by notches into nearly equal-sized lobes. 



Dimensions. — Height, three fifths of an inch ; transverse diameter, one inch and 

 a half. 



Formation. — Coral Rag of Nattheim and Sigmaringen, Wiirttemberg ; of Thurnau 

 and Muggendorf, Bavaria ; of Galgenberg, near Hildesheim, and 

 Lindenberg, near Hanover; of Chatel-Censoir and Druyes, 

 (Yonne) ; Argovien ? of Randen ; " Oxfordien a Belemnites hastatus 

 du Jura Neuchatelois." Desor. 



Collections. — In all the Foreign Collections of Jurassic Fossils. The specimen 

 whence the diagnosis given above has been drawn, was sent 

 me by Dr. Fraas of Stuttgart, as a type of Goldfuss's species. It 

 was collected from the White Jura S and e of Sigmaringen. 



In this specimen the pores are unigeminal in the upper part of the zones, as in the 

 one figured by Goldfuss ; but as several plates belonging to the upper part of the areas 

 are absent, and the pores at the same time are much concealed by the matrix, the 

 bigeminal arrangement may nevertheless have existed in this specimen. In another 

 small Diadem from the Coral Rag of Nattheim, sent me by Professor Roemer, from the 

 Bonn Museum, as typical of Goldfuss's species, the pores are distinctly bigeminal ; in a 

 third specimen, from the Coral Rag of Druyes, sent by M. Cotteau, the pores are like- 

 wise bigeminal. I have not cited the specimens so beautifully figured as Diadema 

 subangulare, by M. Agassiz,* because they certainly are not identical with Goldfuss's type ; 

 they more probably belong to Pseudodiadema versipora of the English Coral Rag. 

 Mr. Woodwardf says, " We cannot agree with M. Agassiz in considering either of these 

 forms referable to the ' Cidarites sub angular is of Goldfuss ; German specimens agreeing 

 with Goldfuss's figure and description, in the presence of only a single series of pores, are 

 in the British Museum." Whether the diplopodous forms are only a variety, or a distinct 

 species, it is impossible to decide, without a better series of specimens for comparison than 

 I possess at present. 



* ' Echinodcrmes Fossiles de la Suisse,' part ii, pi. 17, figs. 21 — 25. 



t Notes on British Fossil Diademas. ' Mem. of the Geological Survey,' Decade Y. 



