Reproductive characteristics of the African pygmy hedgehog, Atelerix albiventris

To obtain further perspective on reproduction and particularly gamete funct ion among so-called primitive mammals presently grouped in the Order Insect ivora, we have examined the African hedgehog, Atelerix albiventris, in ligh t of unusual features reported in shrews and moles. Atelerix proves to shar e many but not all of the characteristics seen in these other insectivores. The penis of Atelerix has a 'snail-like' form, but lacks the surface spine s common in insectivores and a number of other mammals. Hedgehog spermatozo a display an eccentric insertion of the tail on the sperm head, and they ma nifest the barbs on the perforatorium that, in shrews, probably effect the initial binding of the sperm head to the zona pellucida. As a possible corr elate, the structural matrix of the hedgehog acrosome comprises only two ma in components, as judged by immunoblotting, rather than the complex of pept ides seen in the matrix of some higher mammals. The Fallopian tube of Atele rix is relatively simple; it displays only minor differences in width and i n the arborized epithelium between the isthmus and ampulla, and shows no ev idence of the unusual sperm crypts that characterize the isthmus or ampulla , depending on the species, in shrews and moles. In common with other insec tivores, Atelerix appears to be an induced ovulator, as judged by the ovula tion of some 6-8 eggs by about 23 h after injection of hCG. The dense cumul us oophorus appeared to have little matrix, in keeping with the modest dime nsions of the tubal ampulla and, while it was not quite as discrete as that of soricids, it did show the same insensitivity to 0.5% (w/v) ovine or bov ine hyaluronidase.