The aim of the present publication is to summarize the results of studies of ontogenesis of the skeleton and muscles of the human hand and foot. Our primary interest in studying the muscles arose from observations of variations, in which a new form of the anomalous muscle in the popliteal fossa had been described (Cihak, 1954; Hnevkovsky and Cihak, 1957) and in which changes of muscle forms in the congenitally malformed extremity had also been studied (Brlickova and Cihak, 1956). The desire to clarify muscle variations by means of the onto genesis led to a study of ontogenesis of single muscles. During observation of the embryonic pectoralis major special muscle bundles were primarily observed, which could be homologised with the sphincter colli muscle of lower Mammals. Further observation revealed that this muscle (concordantly with its phylo genetic development) gradually develops in the course of human ontogenesis from a small primordium to its maximal extent and becomes reduced thereafter and finally disappears, still during the embryonic period (Cihak, 1957). This study was decisive for the further development of our theme, since it demonstra tes, how consistently in the development of the locomotor apparatus the rule of recapitulation is asserted and how this can be employed in developmental studies of muscles.

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Issues for 1977-1979 include also Special List journals being indexed in cooperation with other institutions. Citations from these journals appear in other MEDLARS bibliographies and in MEDLING, but not in Index medicus.

Cytological techniques have greatly improved in the last twenty years, largely as a result of further development of the microscope. Electron microscopy, in particular, has opened up great prospects for the study of cell morphology, while the develop ment of radio-immuno-assay has brought great progress in endocrinology. The applica tion of these two techniques, which are complementary to each other and provide mutually supporting evidence, is the subject of this monograph. The work is divided into two parts. The first deals with the ultrastructure of normal testicular development, describing four main elements of the testicle - the germ cells, the Sertoli cells, the peri tubular connective tissue and the Leydig cell- with details of their individual development. To make the electron micrographs more easily understandable, diagrams have been used to explain the most important points. The second part deals with cryptorchid testicles, including the primary and sec ondary changes involved and morphometric studies of the secondary changes. The significance of these ultrastructural observations for the treatment of cryptorchidism is emphasized. With the aid of radio-immuno-assay the level of testosterone in cryp torchid mice was determined and comparisons drawn between the ultrastructural changes in cryptorchidism in mouse and man. The experimental studies served as a basis for the hypothesis that, in all probability, a congenital disturbance of the hy pothalamo-hypophyso-gonadal axis is responsible for cryptorchidism. I hope that this monograph will contribute towards a better understanding of normal and cryptorchid testicular development and of the etiology of cryptorchidism.

The establishment of the morphologically and physiologically intimate contact be tween two genetically different individuals, mother and embryo, which takes place during implantation, has always exerted a fascination on researchers in biology and medicine. Recent years have also seen the beginnings of a more practice-oriented med ical interest in this event, as certain methods of contraception whose use is ever in creasing, namely intra-uterine devices (IUDs) and post-coital oral contraceptives, are based on it. On one hand, we have fairly well substantiated experimental and clinical evidence that the efficacy of these contraceptives lies with other factors as well, for example their influence on sperm migration and capacitation or their influence on the transportation of the unfertilized egg. On the other hand there appears to be more im portance in their influence on the blastocyst and on the early stages of implantation (Carol et aI. , 1973; Duncan and Wheeler, 1975; Hafez and Evans, 1973; Oettel, 1975). These stages in development are characterized by complex interactions between em bryo and mother, which have only lately been more exhaustively investigated and which are still subjects of intense research (Beier, 1973, 1974a; Blandau, 1971a; Finn and Porter, 1975; Hafez and Evans, 1973; Steven, 1975). It is expected that insight in to the mechanism of the action of postcoital contraceptives and a possible basis for the development of new concepts in contraception can be gained here.

First multi-year cumulation covers six years: 1965-70.