McLachlan, I. R.2014-12-192014-12-1919730078-8554http://hdl.handle.net/10539/16038A problematic group of microfossils has recently been recovered from strata of Permian age, in the northern part of the Karroo basin in South Africa. This article attempts to present the information that is presently known about them. They have been found in a wide variety of sediments in the Lower, Middle and Upper Ecca stages, and in carbonaceous sediments in the lower part of the Beaufort series. The external morphology of the microfossils is extremely varied, but they are characterized by a regular cup-shaped organ. They closely resemble forms called Anellotubulata by O. Wetzel (1959), who described them from the Upper Lias (c) of Germany. Other workers have recovered, but not described, similar microfossils from Permian, Triassic and Cretaceous strata in Australia. In this paper, the microfossils are referred to as anellotubulates. They are remarkable in a number of respects, the most extraordinary of which is their composition. Electron-microprobe and X-ray diffraction tests have shown the shell to consist of a non-crystalline mineral or minerals, composed mainly of iron and phosphorus, with minor calcium. It has not been possible to demonstrate clearly whether this is the original shell composition, or whether it has resulted from replacement. The available information, including that provided by associated fossils, which has bearing on the palaeoenvironment of the anellotubulates, is discussed. It is hoped that, when more information is available, these problematic microfossils will contribute towards a better understanding of the depositional environment of the sediments in which they occur.enArticle