Certain conclusions on distribution and migration have been reached by Dr. W. K. Spencer2 from his detailed studies of Palaeozoic Asterozoa and in conversation he has frequently expressed the wish that he might be able to compare these with data derived from similarly focused studies of other animal groups. It is reasonable to assume that the final story of migration of faunas in the Lower Palaeozoic British area cannot be told until the inequalities of fossil-collecting and naming have been overcome and until more is known of the stratigraphical position of certain faunas; any conclusions made at the present stage are tentative and are offered as an incentive to research.

During a recent survey of the Lower Old Red Sandstone lavas of North Fife a small unrecorded mass of diorite was found by Dr. F. B. A. Welch. The rock of this intrusion is so much fresher than that of other diorites in the Ochil range that it seems worth while to give an account of its mineralogy and petrology.

It seems late in the day to ask the International Commission to standardize the use of Rhacophyllites in the interpretation commonly accepted for over half a century, but until I discussed this genus last summer with Dr. S. W. Muller, Stanford University, California, in connection with work on Lias ammonites, I was unaware that it offered a nomenclatorial problem or that this was incapable of a simple solution on the basis of the existing rules of nomenclature. A discussion of the difficulties encountered may not be out of place in this series, and I hope to show that this is indeed one of the special cases in which standardization provides the only fair solution.

In the brachiopod family Strophomenidae, it is recognized that various genera, of which Leptaena Dalman is a good example, may possess a foramen enclosed within the umbo of the ventral valve, near the apex of the pseudodeltidium (see Text-fig. 2 A). Such a foramen is presumably a pedicle-aperture, and bears a superficial resemblance to that of certain Telotremata in which the young pedicle emerged through the open delthyrium and subsequently resorbed the apex of the ventral valve and became enclosed dorsally by the deltidial plates. In the young stages of Leptaena, on the other hand, the foramen was entirely supra-apical and enclosed within the ventral protegulum and nepionic shell, though sometimes it later suffered resorption of its dorsal margin so as to become bounded by the pseudodeltidium.