﻿FROM THE CORALLINE OOLITE. 405 



closed again by crystallization in the rock ; the base is nearly entirely concealed by adhering 

 matrix. 



Affinities and differences. — The flatness of the upper surface and the form of the 

 ambulacral areas in this species closely resemble Pygurus Hausmanni, but the test is 

 narrower before, wider near the middle, and more rostrated posteriorly, than the usual 

 specimens of that large species. I have, therefore, described it under a distinct name, 

 not, however, without misgivings of its propriety, as a series of specimens might exhibit 

 intermediate links, by which the two forms would blend into one type. This is one of 

 the many difficulties to be encountered in describing new species from single examples, 

 which in the present instance is unavoidable ; time and additional specimens, however, 

 will prove how far my doubts are well-founded or otherwise. 



Locality and Stratigraphical position. — This species was collected from the Coralline 

 Oolite at Malton, Yorkshire, where it is extremely rare ; the specimen I have figured is 

 the only one I have seen. 



History. — This urchin was first recorded in my memoir ' On the Stratigraphical Distri- 

 bution of the Oolitic Echinodermata,' afterwards published as one of the ' Reports of the 

 British Association for the Advancement of Science/ for the year 185G. It is now figured 

 for the first time, and dedicated to my learned friend, Professor John Phillips, of Oxford. 



Pygurus Hausmanni, Koch and Bunker. PI. XL ; PI. XXX, fig. 2. 



Clypeaster Hausmanni. Koch and Dunker, Versteinerungen des Ool. Gebirg., tab. iv, 



fig. 3, p. 38, 1837. 



— — Leymerie, Stat. Geol. et Min. du dep. de l'Aube, p. 239, 1846. 



Pyguuus Hausmanni. Aga*siz et Desor, Cat. raisonne des Echinides, An. des Sciences 



Naturelles, 3 e serie, torn, vii, p. 162, 1847. 



— — D'Orbigny, Prodrome de Paleontologie, torn, ii, p. 26, 14 e etage, 



1850. 



— — Cotteau, Note sur les Echid. de l'etage Kimmeridg., Bull. Geol. 



Soc. de France, 2 e serie, torn, xi, p. 317, 1853. 



— — Forbes, in Morris's Catalogue of British Fossils, 2d ed., p. 83, 



1854. 



— — D'Orbigny, Paleontologie Franchise Ter. Cretaces, t. vi, p. 301, 



1856. 



— — Cotteau, Etudes sur les Echinides Fossiles, p. 328, 1856. 



— — Desor, Synopsis des Echinides Fossiles, p. 314, 1858. 



— giganteus. Wright, Oolitic Echinodermata, Report of the British Associa- 



tion for the Advancement of Science for 1856, p. 396. 



