4 



BRITISH FOSSILS. 



2. H, Baihji, Forbes, MS. Morris's Cat., 2nd edit. p. 81. Holaster argillaceus (part), 

 Morris's Cat, 1st edit. p. 54. Echino-spatangus, Mantell, Geol. Sussex, p. 86. 



The specimens of this Hemiaster are all more or less crushed, but the most perfect 

 agree in their proportions with the figured specimens of H. Murchisonice. One 

 example, of the size of the figure, has the same number of ambulacral pores as 

 specimen B., viz. 26, 36, 22. The peripetal fasciole is quite distinct, narrow, and 

 simple in its contour, passing from end to end of the ambulacral petals, and only 

 slightly contracted at the sides. The surface of the G ault urchins is usually rough, 

 with nodular concretions of iron pyrites formed upon the tubercles. So many of 

 the Blackdown fossils are identical with species of the Folkstone Gauit, that we 

 have felt considera,ble hesitation in admitting as specific, a character which may 

 by any possibility be due to the mineral condition of the specimens. 



Localitij. — Gault, Tolkstone. 



3. H. Morrisii, Forbes, MS. Morris's Cat., 2nd edit. p. 81. Echinospatungus cordi- 

 formis (part), Mantell, Geol. Sussex, p. 108. Hemiaster punctatus, D'Orb. Ter. Cret., 

 pi, 886. ? (no description). Spatangus complanatus, Mantell, Medals, 1st edit. p. 355. (not 

 figured). 



This not uncommon species has been long known to English collectors by a variety 

 of incorrect names, but it is entirely distinct from any species with v/hich we have 

 been able to compare it, except the Hemiaster punctatus of D'CJrbigny, the descrip- 

 tion of which has not yet appeared. The largest specimen of Dr. Manteli's 

 measures in length 2|-, breadth 2, height, if inches. One of ordinary dimensions 

 measures Ion. 17, lat. 16, alt. 10 lines. The outline is oval and slightly polygonal; 

 the anterior sulcus broad and obscure ; the posterior end flat, and sloping at an 

 angle of 70° (not vertical as in H. punctatus). The underside is but slightly 

 flattened, the margins tumid, the vertex depressed and central. The ambulacral 

 petals are small, moderately impressed, and surrounded by a distinct fasciole, which 

 passes from point to point with scarcely any curvature. The surface, when well 

 preserved, is rough with unequal tubercles, which are perforated, seated on 

 crenulated bosses, and surrounded by a sharply-defined plain ring ; they are so 

 crowded as seldom to allow the formation of a complete circle of miliary granules. 



Localities. — Lower Chalk, Dover (Mus. Pract, Geol.) and Hamsey, Sussex (Brit. 

 Mus. Mantellian Collection). 



4. H. bucardium, Goldf. sp. (sec. Bronn, Index, p. 723.) Micraster lacanosus, 

 Morris's Cat, 1st edit. p. 55. (not Parkinson). 



This fine species is omitted in the second edition of the Catalogue of British Fossils ; it 

 agrees very well with the figures of Goldfuss. In the British Museum there is a 

 single specimen of another species, equalling H. bucardium in size, and apparently 

 undescribed. 



Locality. — Upper Green Sand, Warminster. 



S. P. Woodward. 



March 1856. 



