A. E. V err-ill Decapod Crustacea of Bermuda. 375 



10. Posterior distal spine of merits of chelipeds obsolete or reduced to a 



tubercle ..... ____ _____ ................ tumidula ; depressifrons ; Sayi 



11. Manus of chelipeds with two distal spines, one behind the other. 



anceps ; (ventralis) ; sulcatus ; Sebce 



12. Manus with three distal spines, each on a different rib ......... . ---- rabra 



13 Manus with a brilliant silvery or iridescent area on the superior outer 



surface ............ - - ..... - ...................... - - Ordwayi 



14. Inner spine of carpus more than half as long as nianus ........ spinicarpus 



15. Ambulatory legs long, oar-like, with the three distal segments wider, 



much flattened, and strongly fringed on the under margin ..... ---- Sayi 



16. Swimming (posterior) leg with an erect acute spine on the basal joint. 



Sebce 



17. Swimming legs having the posterior distal end of merus angular and armed 



with a sharp spine ......... _____ spinimanus (spine small) ; rubra ; Sebce 



IS. The same, armed with a row of small, often unequal denticles. 



spinimanus ; Smithii ; tumidula; Gibbesii ; Ordwayi 



Analytical table of the Bermuda species of Portunus, Achcloils, and Charybdella. 



A. Frontal teeth six, counting the inner orbitals, which are not bilobed. 



B. Anterior ambulatory legs remif orm with the distal segments flat and strongly 



fringed ; merus not flat nor fringed. Carapace wide, with margin broadly 

 arched in front ............ ______ ........... ______ ..... .Genus Portunus 



b. Carapace nearly smooth, glossy, not pubescent ------ ' ......... ........ Sayi 



B'. Anterior legs adapted for walking, not distinctly remif orm, nor much 

 flattened distally ; dactylus slender. Carapace margin more narrowly 

 arched anteriorly ; dorsal surface strongly areolated or sculptured, usually 

 closely covered with short hairs ____ ....... _____ ----- ..... Genus Achelous 



C. Posterior lateral tooth distinctly longer than those in front of it. 



D. Basal joint of posterior legs with a sharp erect spine ; also a straight spine 



on outer distal angle of its merus. Four inner frontal spines prominent. 

 A pair of round red spots on the flanks ___ ......... - ..... -- ........ Sebcn 



D'. Basal joint of posterior legs without a spine ; no large spine on its merus. 



E. Chelae with a smooth, iridescent area on upper outer surface of maims ; a 



single distal spine 011 manus ; four inner frontal teeth prominent ..Ordwagi 

 E'. Chelae without an iridescent area. 



F. Chelae with two distal spines on manus, one before the other ; posterior 



lateral tooth elongated, spiniforni ............. ----------------- ..anceps 



C'. Posterior lateral tooth little or not at all larger than the others. Chelae with 

 a single distal spine on manus. Frontal teeth very short, middle two much 

 smaller ______ ........ ________ ........ _______ _______ ....... depressifrons 



A'. Frontal teeth eight, counting the inner orbitals, which are bilobed, each as 

 two. Carapace sculptured, closely pubescent ; posterior lateral tooth mod- 

 erately elongated ________ .. _____ Genera Achelous (pars) and C'li<ii-i/l><li'l/n 



F. Antero-margiual teeth, except last, equal or nearly so. 



G. Two interior frontal teeth decidedly more prominent than the others. 



G'. Two interior frontal teeth scarcely more prominent than the others. . s,,, illi ii 

 F'. Antero-marginal teeth unequal, alternately larger and smaller. . .C, / m idula 



