TABLE OF CONTENTS 



Page 



Introduction 1 



Explanation of measurements and abbreviations used 4 



The cancroid or cyclometopous crabs of America 5 



Areolate markings on the carapace of crabs 6 



Analogous species on opposite sides of the continent 6 



Species on both sides of the continent 7 



Systematic discussion 8 



Keys to subtribes, superf amilies, and families 8 



Superfamily Brachyrhyncha 10 



Family Euryalidae 10 



Genus Gomeza 10 



Gomeza serrata 11 



Genus Pseudocorystes 11 



Pseudocorystes sicarius 12 



Family Portunidae 13 



Subfamily Carcinidinae 14 



Genus Carcinides 14 



Carcinides maenas 15 



Subfamily Liocarcininae 18 



Genus Ovalipes X8 



Ovalipes ocellatus ocellatus 19 



ocellatus guadulpensis 23 



punctatus 24 



Genus Bathynectes 27 



Bathynectes superba 28 



Genus Coenophthalmus 30 



Coenophthalmus tridentatus 31 



Subfamily Thalamitinae 33 



Genus Portunus 33 



Subgenus Portunus 36 



Portunus sayi 37 



anceps 42 



ventralis 43 



gibbesii 49 



xantusii 50 



acuminatus 56 



asper 36 



panamensis 58 



vocans 60 



Subgenus Achelous 62 



Portunus spinimanus 62 



brevimanus 68 



stanfordi 69 



angustus 70 



ordwayi 71 



minimus 76 



pichilinquei 78 



sebae 79 



affinis 80 



floridanus 82 



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