26 Obituary Notices of Fellows deceased. 



of his drawings and descriptions. The impression which Allman has 

 made upon biological science is of two kinds, that of the specialist in 

 the Hydrozoa and the phylactolaematous Polyzoa, and that of the 

 general biological philosopher. 



Allman's great work on gymnoblastic Hydrozoa, which was published 

 by the Ray Society in 1871-2, is without doubt the most important 

 systematic work dealing with the group of Coslenterata that has ever 

 been produced. The excellence of the illustrations alone would almost 

 justify us in placing this work in the first rank of zoological treatises. 

 The soft and delicate bodies of these zoophytes are such that no method 

 of preservation that is known to us can give to our museums anything 

 but distorted and shrivelled cadavera of the living organisms, nor can 

 the most eloquent description convey to the mind an accurate idea of 

 their form and grace. This being the case, great confusion arises in 

 naming and describing species unless there are some drawings that are 

 absolutely trustworthy in existence, to which reference may be made. 



Allman's drawings of Hydrozoa and of the fresh-water Polyzoa have 

 as a matter of fact become the " types " to which zoologists will refer 

 for many years to come, and as such they are of extreme importance. 



But the great monograph on the Hydrozoa was far more than an 

 excellent illustrated statement of species, for it contained a most im- 

 portant and concise account of the anatomical structure of these 

 animals based very largely upon his own researches. 



The memoir on the structure of Cordylophora lacustris, which was 

 published in the ' Philosophical Transactions ' in 1863, may be 

 regarded as the starting point of that work on Coelenterates which will 

 be particularly associated with his name. It was in this memoir that 

 he clearly defined the two cellular layers of the Coelenterate body-wail 

 and gave to them the names " Ectoderm " and " Endoderm, " which are 

 now so familiar to all students of Biology. To Allman we are also 

 indebted for many useful terms such as " Coenosarc, " " Trophosome, " 

 " Gonosome, " and many others which have a more special application 

 to Hydrozoan structure. Many of his papers and monographs are 

 illustrated in the text by woodcuts, which show, in a diagrammatic 

 form, his conception of the important features of structure and the 

 homologies of the organs of one animal with those of others. Many 

 zoologists have shown their appreciation of this method by copying 

 into their text-books Allman's figures, and by constructing diagrams 

 of the same general type to illustrate their own researches. 



Of his writings that have a more general bearing, perhaps the most 

 important theme was the method to be adopted for the construction and 

 limitation of genera and species. Thirty-five years ago when Allman 

 took up this matter, there was a great deal of very unsatisfactory work 

 on systematic zoology in course of publication. New species and new 

 genera were named in great numbers, many of which were based on 



