IN spite of the three quarters of a million species of animals which have been described binomially, it is remarkable how little there is of organised plan in the descriptions, taken as a whole. Some authors of new species are content with a few lines of characterisation, others seem to describe, not a species, but the total characters of an individual specimen. It is partly that species are not fixed, and that few writers, even on the same group, would agree upon the characters to be selected as criteria of specific rank, partly that the critical characters within different groups appear to be so diverse, that no common plan would fit more than a relatively few. Dr. Severin Icard has made a bold attempt to standardise descriptions of species by advocating a method which he calls “la methode des nombres signaletiques” (Revue de Path. comp. Hyg. gen., Nov. 1934). It looks quite simple. Shortly, it is that, in regular order, parts of the specimen to be identified or described are examined, and the result for each part is represented by a number. The key to the parts to be examined for a particular group, and to the number corresponding to a particular character, say, legs yellow, is to be found in a set of “Tables de correspondance”. Thus the special character of each part has its own particular number, a short-hand way of writing a description which normally would contain at least a few words for each part.