EPIASTER. 265 



Genus — Eptaster, d' Orbigny ,1853. 

 Spatangus (pars), Auctorum. Micraster (pars), Agassiz. 



Form oblong ; test more or less elevated, often cordiform. 



Antero- and postero-lateral pairs of ambulacra petaloidal and lodged in depressions 

 of the test ; the anterior are longer and more developed than the posterior pair. 

 Poriferous zones equal in each ambulacra, composed of elongated pores shorter in the 

 internal than in the external rows. 



The single ambulacrum, lodged in a well-defined anteal sulcus, is composed of pores 

 different from those of the antero- and postero-lateral pairs, as they are mostly round 

 and disposed in pairs set widely apart. 



The apical disc is composed of four perforated genital and five ocular plates. 



Peristome near the anterior border and strongly bilabiate ; the inferior lip thick and 

 prominent. 



Periprocte round or oval, situated at the posterior border, often opening in a 

 distinct area. 



No fascioles. 



Tubercles well spaced out, unequal in size, crenulated, and often scrobiculated ; inter- 

 tubercular area covered with granules. 



The Epiasters have been long confused with the Micrasters, which they resemble 

 much, but differ from that genus in the absence of all fascioles. They are distinguished 

 from Echinospatagus by their ambulacra, which are in the form of enclosed petals, 

 by their poriferous zones, which are equal, and by their peristome, which is markedly 

 bilabiate. 



Epiaster De Loriolii, Wright, nov. sp. PI. LIX, figs. 1, a — g. 



Micraster lacunosus, Morris. Catalogue of British Fossils, 1st ed., p. 55, 1843. 

 Hemiaster btjcardium, Woodward. Mem. Geol. Surv., decade v, pi. ix, notes, 1856. 



Diagnosis. — Test large, cordiform, declining anteriorly, elevated posteriorly ; anteal 

 sulcus deep, grooving the border; ambulacra much depressed. Anterolaterals curved 

 slightly forwards and outwards, and inclined at 45° ; postero-laterals shorter, curved 



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