On two new species of Holectypus Desor from the Senonian of South-Limburg near Maastricht, Netherlands

Up to now the genus Holectypus Desor (1842, p. 52) 1847, (cf. Mortensen, 1948, Monogr. IV 1, p. 26) in its restricted sense (with 4 genital pores) has not been recorded from the Senonian. So the two specimens described below as H. boschmai nov. spec. may have been remaniated and finally deposited in the Senonian of South-Limburg. They then may belong to the Jurassic species H. corallinus d'Orbigny, 1850. Though the preservation of two other specimens of Holectypus from the Limburg Senonian does not permit to decide whether a fifth genital pore is present, it is presumed there was. These two specimens are described as H. macrostomus nov. spec. As said, up to now no Senonian Holectypus is known with 4 genital pores. Holectypus boschmai nov. spec. (pl. XIV) Cf. Holectypus corallinus d'Orbigny, 1850 (see Cotteau, 1873, p. 430, pl. 110, 111). 2 specimens, "Upper Cretaceous, Limburg" (Zoological Museum, University of Amsterdam). Though in their outer form our specimens can be compared with Caenholectypus turonensis (Desor, 1847) and in the form of the periproct with C. macropygus (Agassiz, 1836), (for both see Cotteau, 1861, p. 56, resp. p. 44), they differ in having only 4 genital pores. The better preserved one may be designated as the type specimen. It is 20.5 mm long, 21.0 mm wide, and 11.0 mm high, the paratype is 20.6 mm long, 20.7 mm wide, and 10.6 mm high. The paratype is less well preserved, but the absence of parts of the test here permits to see that there are no such radiating partition walls as in