192 L. A. BORRADAILE. 
I gave the recognised name of “variety,” without attempting to define what that name 
meant. In many of the sections of this series similar groups of individuals occur, and it 
seems well to indicate at the outset what value is put upon them, both for the immediate 
purpose of the better description of the collection in hand, and in the hope of helping other 
workers in the same field. From these considerations there arise certain others regarding 
the ultimate nature and fate of varieties, and I shall endeavour to show in what direction 
my own speculation on this subject has led me. I am well aware that an experience, not 
of four years, but of forty would barely qualify an investigator to speak with sufficient 
authority for his words to carry conviction on such intricate and disputed points. But it 
seems well to indicate in general terms what are the problems involved from the poimt of 
view of the -systematist. 
The first article in the series will therefore be devoted to some remarks on the subject 
of varieties in the Decapoda. The second and following ones will contain the systematic 
lists, and the whole will be brought to an end by a discussion of such general questions 
as may be suggested by the material. Wherever possible the only references will be to 
Major Alcock’s excellent lists of the Indian crabs, which contain full bibliographies and 
accurate descriptions of the species. These papers appeared in the Journal of the Royal 
Asiatic Society of Bengal: Part 1 (Oxyrhyncha) in Vol. Lxiv. i. p. 157 (1895): Part 2 
(Oxystomata) in Vol. LxXv. ul. p. 296 (1896): Part 3 (Xanthidae) in Vol. Lxvi. i. p. 67 
(1898): Part 4 (Portunidae, etc.) in Vol. Lxvui. u. p. 1 (1899): Part 5 (Dromiaceae) in 
Vol. LXvI. ii. p. 123 (1899): Part 6 (Catometopa) in Vol. LxIx. u. p. 279 (1900). A 
reference to this work is to be understood by the mention of Major Alcock’s name and 
the numbers of the part and page of the article referred to. In other cases references will 
be limited, as far as may be, to idicating a single paper in which a reliable synonymy 
may be found. 
The classification adopted is that of Ortmann in Bronn’s “Thierreich,’ with certain 
modifications of my own, proposed in a paper in the Proceedings of the Zoological Society 
for 1900 (pp. 568—596). 
The several sections will not deal with groups of equal taxonomic value, nor will these 
necessarily be considered in systematic order. Section 1, included in the present instalment, 
is devoted to the Swimming Crabs (Portunidae). 
In conclusion I may be allowed to repeat the acknowledgements I have already made to 
the Managers of the Balfour Memorial Fund and the Drapers’ Company of London for their 
aid. Nor can I sufficiently express my obligation to Mr Stanley Gardiner for the assistance 
his great knowledge of tropical marine biology has been to me, confirming, as it has, my 
own less experienced observations, and for much kind advice on other points. 
