438 A. Alcock — Carcinological Fauna of India. [No. 3, 



p. 358 : Ortmann, Zool. Jahrb., Syst., VII. 1893-94, p. 730 : M. J. Rathbun, P. U. S. 

 Nat. Mus. XXI. 1898, p. 605. 



Plagusia immaculata, Lamarck, I. c. p. 247 : Miers, I. c, p. 150, and Challenger 

 Brachynra, p. 273, pi. xxii. fig. 1 : Haswell, I. c. : de Man, Archiv fiir Naturges. 

 LIII. 1887, i. p. 371 : Cario, Boll. Soc. Nat. Napol. III. 1889, p. 246 : Henderson, 

 Trans. Linn. Soc, Zool., (2) V. 1893, p. 391 : Ortmann, I, c. : Nobili, Ann. Mus. 

 Genov. (2) XX. 1899, p. 271. 



Plagusia depressa, Latreille (nee Fabr.), Encycl. Meth. X. 145 : Milne Edwards, 

 Hist. Nat. Crust. II. 93, and Ann. Sci. Nat., Zool., (3) XX. 1853, p. 179 : Heller, 

 Novara Crust, p. 51. 



Plagusia orientalis, Stimpson, Proc. Ac. Nat. Sci. Philad. 1858, p. 103, and Ann. 

 Lye. Nat, Hist. New York, VII. 1860, p. 231. 



All the regions of the carapace are distinct, and the surface is 

 covered with flat pearly or squamiform tubercles which are fringed 

 anteriorly with little close-set bristles of uniform length. 



The tubercles vary : sometimes they are prominent, sometimes 

 depressed, and sometimes they are almost obsolete on the most convex 

 portions of the carapace. The little fringes of bristles also vary: some- 

 times they fill all the space between the tubercles, somtimes they can 

 only be made out with a lens, sometimes they are absent. 



The antero-lateral border of the carapace is armed with four teeth 

 (including the orbital angle) which decrease in size from before back- 

 wards. The epistome is prominent beyond the anterior border of the 

 carapace and is usually cut into seven lobes. 



The chelipeds of the adult male are massive and are about half 

 again as long as the carapace, but in the female they are slender and 

 only about as long as the carapace. The inner angle of the wrist is 

 coarsely dentiform : the tubercles on the upper surface of the palm and 

 dactylus are arranged in high relief in longitudinal rows, those on the 

 outer surface of the palm — especially at the upper part of it — have a 

 tendency to fall into transverse rows. 



On the posterior edge of the dorsal surface of the basipodites 

 of the legs is a subacute tooth or blunt lobe with entire edges, this tooth 

 "being most conspicuous in the 2nd and 3rd pair of legs : on the anterior 

 border of the meropodites there is a single strong spine, subterminal in 

 position : the upper surface of the carpopodites propodites and dactyli is 

 traversed longitudinally by a dense strip of long bristles. The 3rd pair of 

 legs, which are the longest, are not quite twice the length of the carapace. 



In the Indian Museum are 31 specimens from the Bay of Bengal 

 and Arabian Sea: many of them were taken from drift timber in the 

 open sea. Old specimens are commonly encrusted with barnacles and 

 acorn-shells. The largest specimen in the collection has a carapace 

 54 millim, long and 56 broad. 



