MARINE CRUSTACEANS. 245 



fringe such descriptions in small points only. The phenomenon of local variation in Pilumnus 

 deserves, and would repay, careful investigation, especially with regard to the existence of 

 intermediates, their number relative to those of the described forms, and their distribution, 

 whether they be found in intermediate localities or no. In short, information is needed as 

 to whether the subspecies of Pilumnus be " discontinuous," like true varieties, or no. 



The members of the genus live under stones, in coral blocks, etc. 



6. Pilumnus vespertilio (Fabr.) 1793. Alcock, III.' p. 192. 



The fur of the Maldive specimens is not dark, as in the type, but of a golden-yellow 

 colour, like that of Alcock's Karachi and Tavoy race. At the same time the usual smooth patch 

 is to be found near the base of the finger of the large hand. Perhaps these characters are 

 distinctive of local races or subspecies of P. vespertilio. 



The species, which is sluggish in its habits, lives under stones, etc., and was taken on 

 the reef at Hulule, Male Atoll, and in Funadu Velu, Miladumadulu. 



7. Pilumnus andersoni de Man, 1887. subsp.^ See Alcock, ill. p. 194. 



The Maldive specimens differ from the race defined by Alcock in the following points : 



(1) There are no granules on the carapace, which is everywhere smooth and finely pitted. 



(2) The spines on the fore edge of the meropodites of the walking legs are vestigial, and 

 there is no spine at the end of the joint. (3) The arrangement of the spines on the fore 

 edge of the arm does not agree with that described by de Man. Alcock does not mention 

 these spines, but, as he cites de Man's paper, it is presumable that all his specimens presented 

 the same arrangement as the type. In the Maldive example there is a row of strong, blunt 

 teeth, growing smaller from without inwards. In de Man's specimens there were two, large, 

 arched, sharp spines at the outer end, with a small spine at the base of the distal of the 

 two. The more proximal was larger than the distal one, and behind it were four or five 

 acute granules. 



Dredged in .5 — 39 fathoms in Minikoi, South Nilandu, and Haddumati Atolls. 



8. Pilumnus hirsutus Stimps, 18.58. subsp. See Alcock, in. p. 197. 



The Maldive specimens differ from those on which Alcock's description was founded in the 

 following points: (1) A small subhepatic tooth is present. (2) The gaps on the orbital edge 

 are fairly distinct. 



According to Haswell {Cat. Austral. Crust, p. 69), the meropodites of the walking legs of 

 this species should bear three or four spines. Alcock does not mention these spines, and they 

 are wanting in the Maldive specimens, in which the fore edge of the meropodite is roughened 

 by a row of low, blunt teeth. Alcock is doubtful about the identity of the species he is 

 describing as P. hirsutus, and it seems likely that the three forms ' are -distinct. 



A single specimen from South Nilandu, which bears a Sacculina, differs from the others 

 in the following points : (1) The antennal flagella are long and hairy. (2) 'The large hand 

 is rather less " full." (3) The body is rather flatter. (4) The legs are a little longer. 



' Journ. As. Soc. Beng. lxvii. ii. pp. 67 — 233 (1898). For include species, subspecies, and varieties. In this sense it 



the principle on which references are given in this paper see is a useful counterpart of "group," used to include all 



Vol. I. Part II. p. 192 of the present publication. divisions of the animal kingdom from genera upwards. For 



^ See footnote to p. 195 of Part II. of this publication. definition of " variety " and " subspecies " see the article on 



' I am using the word "form" in its broadest sense to Varieties in Part II. of this publication. 



