Boone, Crustacea, Cruises of "Eagle" and "Ara," 1921-28 191 



second is reduced, the first (orbital), third and fourth are long, strong, 

 triangulate teeth. The chelipeds of dovii are much slenderer than 

 those of rohustus; the spines on the anterior lateral margin of the 

 merus of dovii are much feebler than those of robustus. 



Distribution : West Coast of Central America (type locality) ; 

 down to Peru. Rare. 



Material examined: One male taken in-shore, Wafer Bay, Cocos 

 Island, March 5, 1926. 



Color: Adult male — carapace nigrosin violet, shading into litho 

 purple toward the edges and on the legs ; frontal and lateral areas of 

 body and basal two-thirds of first, second and fourth natatory legs 

 pleroma violet shading into lavender violet. Terminal joints of fourth 

 natatory legs coral red shading into pleroma violet basally. Chelipeds 

 pleroma violet ventrally, light magenta dorsally on the basal half; 

 carpus, propodus and fixed fingers deep vinaceous red; both fingers 

 conspicuously marked with malachite green. Eyestalks litho purple ; 

 cornea shining, lilac gray. 



Habits : Far out at sea, where the endlessly shifting miracle of in- 

 describably exquisite colors jewel the Pacific, the loveliest of the swim- 

 ming crabs, Euphylax dovii, makes its home. One half glimpses a 

 fragile, amethystine creature pulsing with sea-rhythm through the 

 amethystine lights and shadows. Closer inspection reveals the exceed- 

 ing length and slenderness of limb and delicately delineated carapace 

 that typify the strong swimmer. From the powerful, long, slender, 

 splendidly toothed claws one may infer that this species is aggressively 

 predatory. 



Technical description : Adult male : The carapace is irregularly 

 oval, with the anterolateral margin evenly rounded and ornamented 

 with four small teeth and the postlateral margins decidedly conver- 

 gent. The interorbital region is decidedly narrow between the bases 

 of the eyestalks, but widens immediately beyond into a T-shaped 

 process, which latter has its frontal margin relatively straight, lightly 

 carinated, with a minute median notch. The frontal margin of the 

 carapace on either side of this process is finely beaded; behind this, 

 for distance equivalent to the length of the eyestalk, there is a strip 

 of dorsal surface of the carapace whose inner angulated edge forms 

 the inferior margin of the cavity into which the eyestalk fits; the in- 

 ferior orbital margin below the cornea is decidedly concave, finely 



