Ediiiondsoii — Cnislacai from Palmyra and faiiiiiitg Islands 39 



at the Maldive Islands; and ^1/. i;^ardin('ri Ratlibun," from Salomon Island, 

 western Indian Ocean. In ^1/. symbioticai the length and width of the 

 carapace are subequal and the chelipeds of equal size. M. gardineri is 

 more nearly like the new species, having an oval carapace and unequal 

 chelipedes : it has, however, a more deflexed front with a slighter median 

 emargination ; the antero-lateral margin is smoother, without spinules 

 between the interspaces of the four teeth ; the whole outer surface of the 

 nianus is rough, the protuberances of the major manus being bead-like 

 tubercles and granules, while those of the minor manus are more or less 

 conical, but not so sharp and spinelike as in ('almyrensis ; the fingers of 

 major chela are rough except near the tips, tubercles beadlike or slightly 

 pointed ; the fingers of the minor chela are broader than in palmyrensis, 

 prehensile edges entire, immovable finger smooth and punctate. In both 

 of the oval species, the merus of the outer maxilliped is broader than long; 

 in gardineri the anterior margin is nearly straight outside the notch and 

 rounds into the outer margin ; in [>almyrcnsis the anterior margin is con- 

 vex outside the notch. 



The armature of the ambulatory dactyls is similar in these two species, 

 indicating a habitat akin to that of the type-species. 



Charybdis (Charybdis) cookei, sp. nov. 



Type. — Male; Palmyra Island; C. M. Cooke,- collector ; type-specimen 

 in Bishop Museum, No. 983. 



In the subgenus Charybdis (=Goniosoma Alcock)'^ there are combined 

 the following characters: The antennal flagellum is completely excluded 

 from the orbital hiatus ; the ridge that bounds the dorsum of the carapace 

 posteriorly forms a curve with the postero-lateral borders ; and there is 

 no spine on the posterior border of the arm. Our species belongs to that 

 section of the subgenus which has a ridge on the cardiac region and to 

 that subsection which has also a ridge or two on the posterior half of the 

 branchial region. 



The species is of small size ; carapace pubescent, the three anterior 

 transverse ridges strong, the cardiac ridge blunter, continuous, the single 

 branchial ridge short, not far from, and a little in advance of, the cardiac 

 ridge. Of the frontal teeth, those of the median pair are narrow, arcuate ; 

 those of the submedian pair wide, subtruncate, a little oblique, less ad- 

 vanced ; antennal pair narrower, more triangular and still less advanced ; 

 orbital pair least advanced, broad, obliquely triangular, tip rounded. Upper 

 margin of orbit with two open, triangular marginations. Five antero- 



" Trans. Linn. Soc. London, ser. 2. vol. 14. 19n. p. 233, pi. 19, tigs. 5 and 6. 

 ''Journ. Asiat. Soc. Bengal, vol. 68. 1899. p. 49. 



