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HEMIASTER. 



Hemiaster Bailyi, Forbes. PI. LX, fig. 2. 



Echinospatangus, Man tell. Geology of Sussex, p. 86, 1822. 



Holaster argillaceus, Morris (pars.), Catalogue Brit. Foss., 1st ed., p. 54, 1843^ 

 Hemiaster Bailyi, Forbes. Morris, Catalogue, 2nd ed., p. 81, 1854. 

 — — Woodward. Mem. Geol. Surv., decade v, 1856. 



The specimen figured in this plate belongs to the Museum of the Royal School of Mines, 

 and is so much crushed and its characters defaced that I am unable to give a correct 

 diagnosis of the species, and now figure it as the authentic example of my late friend's 

 species. The outline figure and general contour of the test resemble Ecldnospatagus 

 Murchisonianus. " The peripetalous fasciole is narrow, distinct, and simple in contour, 

 passing from end to end of the ambulacral petals and only slightly contracted at the 

 sides. The surface of the Echinidae from the Gault is in general rough with nodular 

 concretions of iron pyrites formed upon the tubercles. So many of the Blackdown 

 fossils are identical with species of the Folkestone Gault that we have felt considerable 

 hesitation in admitting as specific a character which may by any possibility be due to the 

 mineral condition of the specimens." — Woodward. 



Locality and Stratigraphical Position. — Collected from the Gault at Folkestone ; 

 the type-specimen I have figured is contained in the Museum of the Royal School of 

 Mines. 



Hemiaster asterias, Forbes. PI. LX, fig. 3. 



Hemiaster asterias, Forbes. In Morris, Catalogue, 2nd ed., p. 81, 1854. 

 — — Woodward, Mem. Geol. Surv., decade v, 1856. 



The type-specimen I have figured is not sufficiently well preserved to enable me to 

 form a diagnosis of the species. The vertex appears to have been more prominent and 

 removed more posteriorly than in II. Bailyi, and the dorsal ambulacra are likewise 

 rough and narrower in proportion than in that species. 



Locality and Stratigrap/dcal Position. — Collected from the Gault at Folkestone, 

 where it is rare. The type-specimen I have figured belongs to the Museum of the Royal 

 School of Mines, Jermyn Street. 



