ANIMALS. 53 



Arch^eocidaris Verneuiliana, King. Plate VI, figs. 22-24, 



CiDARis, King. De Verneuil, Bull. Soc. Geol. Fr., 2"" serie, vol. i, p. 25, 1844. 



— „ Geol. Russ., vol. i, p. 221, 1845. 



— Vernexjiliana, King. Catalogue, pp. 6, 7, 1848. 



— Howse, T. N. F. G., vol. i, p. 261, 1848. 



— Keyserlingi, Geinitz. Versteinerungen, p. 16, pi. vii, figs. 1, 2, 1848. 



Diagnosis. — " Interamhulacral plates sub-hexagonal, a little longer transversely than 

 longitudinally. Socket-balls large, perforated, placed on elevated bases. Glenoid 

 circles radiately crenulated. Muscular areas concave, somewhat broad, surrounded 

 with an elliptical border of small tubercles in a single series."^ 



The diagnosis of Archaocidaris Verneuiliana must still remain imperfect imtil 

 specimens more complete than any I have seen are found. 



Not having discovered any specimens with ambulacra, or more than two contiguous 

 rows of interamhulacral plates, it is unsafe positively to consider this species as belonging 

 to the genus in which it has been placed. The sub-hexagonal form of the plates which 

 have fallen under my notice, has principally led me to regard it as an Archceocidaris ; a 

 view which seems to be strongly supported by the corresponding form of the inter- 

 ambulacrals, in two contiguous rows, figured by Geinitz. 



One of the specimens represented (PI. VI, fig. 23) exhibits the longitudinal spaces 

 between the muscular areas with three or four rows of small tubercles, in addition to 

 the " single series" noticed in the diagnosis ; and in the illustrative specimen given by 

 Geinitz, there are two intervening rows. Two kinds of spines occur in the rock 

 containing this fossil ; one is muricated, as in the specimen represented under fig. 24, 

 and the other is finely longitudinally striated.^ The spine figured by Dr. Geinitz 

 appears to be rather different from the one herein represented, but it is probable the 

 difference is in the figure, and not in the fossil. 



Archceocidaris Verneuiliana is a rare species. The only localities where it is found 

 are Tunstall Hill, and Humbleton Quarry, in Shell-limestone. Corbusen, in the under 

 Zechstein, is the single German station recorded for it by Geinitz. 



1 Catalogue of the Organic Remains of the Permian Rocks of Northumberland and Durham, pp. 6, 7, 

 1848. 



2 Through an oversight, an error was committed in my ' Catalogue' as regards the occurrence of the 

 "transversely-ridged" spine therein mentioned. 



