The object in publishing these notes on the Spur-Dog, Acanthias vulgaris Risso, is to show the close resemblance, in the distribution of the sizes and sexes, between this fish and the Hake. The Hake will be dealt with in a future paper.

The work has been done during voyages in which the Hake has been the principal object of research. The data on Dogfish have therefore been collected at odd times during a very busy programme on the Hake, and this must be my apology for inadequacy or discontinuity in the figures presented. I would especially thank my colleague, Mr. W. Johnston, and my friend, Mr. C. E. D. Enoch, for their willing help in this entirely unofficial work; and Mr. J. Armitage Robertson for his help in the arrangement of the text.