434 A. E. Verrill — Decapod Crustacea of Bermuda. 



Petrolisthes armatus (Gibbes) Stimp. 



Porcellana armata Gibbes, op. cit., p. 190, 1850. 



Petrolisthes armatus Stimpson, Proc. Acad. Nat. Sci., Philad., 1858, p. 227; 

 Ann. Lye. Nat. Hist. N. York, vii, p. 73, 1860. Kingsley, Proc. Acad. Nat. 

 Sci., Philad., 1879, p. 406. Ortmann, Zool. Jabr., x, p. 280, 1897. Bene- 

 dict, Anomnra Porto Eico, p. 133, 1901. 



Platk XXVII, Figure 3. Plate XXVIII, Figure 4. 



Color variable; carapace, in life, often yellowish green, with 

 minute white spots, legs similar, except on the last two joints, which 

 have white transverse bands ; under surfaces pale yellow or white, 

 except the large chelae, which are pale blue (C. S. V.). 



Some specimens are dark gray above, finely spotted with Avhite 

 and light gray. Others are I'ed or reddish brown, thickly specked 

 and spotted with white or yellowish white. 



The colors are imitative of the sand, gravel, stones, algae, etc. 



The median tooth of the front is obtuse. There is a very distinct, 

 transverse, granulated ridge across the front. The merus of the 

 chelipeds usually has three (rarely 4) sharp teeth on the inner mar- 

 gin; the outer margin is finel}^ serrulate. 



The chelae are large, flat, angular; the raanus has a distinct, granu- 

 lated, raised line on the outside. 



One of our larger male specimens has the carapace 11.5"""' long; 

 9.5™™ broad ; between orbits, S'"™ ; merus of chelipeds, 10™™ long; 

 lai'ger chela, 18™™ long; 7.3™™ high. The larger chela is stouter than 

 the other, with shorter and stouter digits, which are laterally 

 incurved and slightly crossed at the tips. 



Variety pallidus, nov. 



Many Bermuda specimens differ from the ordinary form in having 

 the carapace nearly smooth, with scarcely any traces of the trans- 

 verse rugae and granules, so conspicuous in the typical form, and 

 in lacking the coarse granules on the outer sui'face of the chelae. 

 The color is usually white or pale yellow. The chelae are the same 

 in form and carinae, and the merus of the chelipeds has three sharp, 

 spaced teeth on the front edge, as in armatus. In most other 

 respects there are no differences between them. Whether it has the 

 same habits was not noted. Length of carapace, 8-10™™. 



This species is very common at Bermuda. It lives under stones 

 and in the interstices and crevices of dead corals, etc. It was in the 

 earh'- collections of J. M. Jones, and has been taken by uearh' all 



