V.—On an African Occurrence of Fossil Mammalia Associated with stone Implements
F. P. Mennell, E. C. Chubb
1907
Geological Magazine
Mennell 8f Chubb-Mammalia found with Stone Implements. 443 var. stipitata, by Pergens & Meunier in 1887 ; the authors divided that species into three varieties, of which the form stipitata has a narrow stem and discoid head like the English specimens. Some workers at Bryozoa would no doubt include the Danian, the French Maastrichtian, and the British Turonian varieties as all members of one species, which would then have the name B. urnula (d'Orb.). 1 But the differences between the specimens
more »
... om these three horizons seem adequate for their specific separation. The B. urnula, the type species of the genus, has a vasiform body, which is convex below and passes gradually into the short stem, while the apertures of the zooecia are on tufts or radial keel-like plates projecting above the body. B. rotaformis, the oldest representative of the genus, has a wheelshaped body on a narrow stem, and the apertures are on vertical teeth on the sides of the body. The Danian forms are very variable in form: the stem is longer and narrower than in B. urnula, but it still passes by a gradual expansion into the body; the usual form of the zoarium is more piriform than in B. rotaformis. Further differences are that in the Danian forms the stem is perforate, and the apertures of the zooecia open on ridges which project but slightly from the disc ; in one specimen of var. stipitata one of the ridges projects upwards as one of the spine-like processes so characteristic of the genus. Though B. rotaformis is variable, the lower side of the body is apparently always concave, whereas in the Danian forms-which I regard as a new species with the name B. pergensi-and in B. urnula the base is always concave. Both Dr. Rowe and Air. C. D. Sherbom, who have collected a considerable number of specimens of B. rotaformis, tell me that they have not seen one with a vasiform body, and my more limited experience has been the same. V.-ON \S AFRICAN OCCCRKKXCE OF FOSSIL JIAMMALIA ASSOCIATED WITH S I O X E IMPLEMENTS.
doi:10.1017/s0016756800133849
fatcat:ewewdusgczdbpplpuojia7djwa