. 1. E. Yen-ill Decapod Crustacea of Bermuda. 373 



Zoology, from the collection of A. S. Bickrnore, made about 1862. 

 We were unable to find it or learn of its presence there, nor has it 

 occurred in any of the other Bermuda collections that I have seen.* 

 It is the common edible crab of the Atlantic coast, abundant from 

 Southern Kew England to Florida, Louisiana and Texas. 



It ranges to Brazil. f Rio Grande (Miss Rathbun ; also in Yale 

 Mus.). It often ascends estuaries to points where the water is very 

 brackish. Very abundant in Chesapeake Bay, where it is fished on 

 a great scale. 



Portunus Fabr. and Achelous De Haan, 1833. 



Some of the distinctions between Portunus (Fabr., 1798, as now 

 restricted) and Achelous (type A. spinimanus) are neither very 

 definite nor constant. The species intergrade in soma of the charac- 

 ters. In respect to the form of the carapace, which in typical 

 Portunus is more broadly arched, "the center of the arc near the 

 posterior end," the proportions change greatly with the growth. 

 Young specimens of some species would thus fall in one group 

 (Achelous) and the broader adults in the other. A. anceps, of the 

 sizes usually taken, is nearly intermediate in form, if the long lateral 

 spines be not reckoned in the measurements, but it lacks the flat 

 remiform front legs of /Sayi. 



In P. itayi, however, we see a distinctly remiform character of the 

 anterior two pairs of ambulatory legs. They have the basal joint 

 and merus smooth and nearly terete, while the three terminal seg- 

 ments are much flattened and strongly fringed with hairs on the 

 edge, thus adapting them specially for swimming. This would seem 

 to be a true generic character, for in the species of typical Achelous 

 the distal segments of the legs are tapered and grooved, with the 

 dactylus slender and sharp, and therefore adapted for walking. 



To this may be added the character of the merus of the outer 

 niaxillipeds, which in Achelous is prolonged beyond the insertion of 

 the palpus and is angular outwardly, while in P. iSaui it is not pro- 



* Mr. Witmer Stone, in Heilprin's " Bermuda Is..' 1 p. 147, recorded two small 

 males of ll Neptunus hastatus." They may have been Portunus Sayi or Calli- 

 ni-ffca ornatns, but probably not this species. 



Hurdis, Rough Notes and Mem., 1897, p. 361, gives Lupa diacantha as a 

 Bermuda species in his brief list of Crustacea, but his names of the Crustacea 

 are very unreliable. (See Bibliography, below.) 



f Miss Rathbun (1896) established a variety or subspecies acutiili'/is for a 

 South American form, having sharper lateral teeth. This variety extends from 

 the Bahamas to Rio Janeiro. 



