A. E. Verrill — Decapod Crustacea of Bermuda. 375 



10. — Posterioi" distal spiue of merns of chelipeds obsolete or reduced to a 



tubercle tumidula ; depressifrons ; Sayi 



It. — Manus of chelipeds with two distal spines, one behind the other.' 



anceps ; (ventralis) ; siilcatus ; Sebce 



13. — Manus with three distal spines, each on a different rib ._ rubra 



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



surface Ordirayi 



14. — Inner spine of carpus more than half as long as manus S2)inicarpus 



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) l^g 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 sjjinimanus (spine small) ; rubra; Sebce 



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



spiiiimanus ; Smithii ; tumidula ; Gibbesii ; Ordwai/i 



Analytical table of the Bermuda species of Portuniis, Acheloiis, and CharybdeUa. 



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



B. Anterior ambulatory legs remiform 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 remiform, 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 Acheloiis 



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 Sebce 



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



E. Chelee with a smooth, iridescent area on upper outer surface of mauiis ; a 



single distal spine on manas ; four inner frontal teeth prominent. -Orrfu'«gi 

 E'. Chelae withoiit an iridescent area. 



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



lateral tooth elongated, spiniform.. anceps 



C. Posterior lateral tooth little or not at all larger than the others. Chelas 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 Acheloiis {pars) and CharybdeUa 



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



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



spinimanus 

 G'. Two interior frontal teeth scarcely more prominent than the oth.ey:fi.. Smithii 

 F'. Antero-marginal teeth unequal, alternately larger and smaller C. tumidula 



