. Bulletin of the Natural Histort Museum. Geology series. Fig. 15 Camera lucida drawing of plating in Offaster leymeriei Cotteau, 1887 from the Maastrichtian of the coast west of Cabo Mayor (Santander, Cantabria). BMNH EE6170. a, apical surface; b, oral surface. Interambulacra shaded. Scale bar = 5 mm. Occurrence. ince, Spain. UpperThanetianofCasasdeOraien,Navarraprov- Hemipneustes striatoradiatus (Leske, 1778) Material studied. B MNH EE6174-75. Remarks. Although both specimens are incomplete, the cordi- fonn outline and distinctive plastron plating are indicative of just two holasteroid taxa,
. Bulletin of the Natural Histort Museum. Geology series. Fig. 15 Camera lucida drawing of plating in Offaster leymeriei Cotteau, 1887 from the Maastrichtian of the coast west of Cabo Mayor (Santander, Cantabria). BMNH EE6170. a, apical surface; b, oral surface. Interambulacra shaded. Scale bar = 5 mm. Occurrence. ince, Spain. UpperThanetianofCasasdeOraien,Navarraprov- Hemipneustes striatoradiatus (Leske, 1778) Material studied. B MNH EE6174-75. Remarks. Although both specimens are incomplete, the cordi- fonn outline and distinctive plastron plating are indicative of just two holasteroid taxa, Cardiaster or Pseudholaster. Cardiaster has the labral plate and first sternal plate arranged uniserially, whereas Pseudholaster has the labral plate extending to touch the outer edge of the second labral plate. Furthermore, Cardiaster has a marginal fasciole that disappears towards the anterior, whereas Pseudholaster has no fascicles whatsoever. Unfortunately, preservation is so poor that the presence or absence of a marginal fasciole towards the posterior of the test cannot be confirmed. Plastron plating, however, is more decisive, in that the labral plate appears to be short and well separated from the second sternal plate. For this reason we assign the specimens to Cardiaster. Our specimens differs from the common Maastrichtian Cardiaster granulosus (Goldfuss) in having a wider plastron with plates in each column extending less far towards the opposite ambulacrum. It also lacks enlarged primary tubercles running up the aboral surface of the anterior interambulacra, which are characteristic of C. granulosus. Genus HEMIPNEUSTES L. Agassiz, 1836 Diagnosis. Test cordate with flat base and domed upper surface. Apical disc elongate with four gonopores; madrepores typically extend over the anterior two genital plates. Paired ambulacra petaloid with petal columns strongly unequal, the posterior column of pore- pairs always being very much better developed. The anterior petals are
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