membrane between the coxa of an appendage and 

 the body wall. 



Basis (basipodite) . — Second article (from the 

 body) of a leg or maxilliped. Sixth segment from 

 distal end of the limb. 



Basicerite. — Spine on dorsal side of basis of an- 

 tenna ; sometimes more lateral than dorsal. 



Branchiocardiac groove. — Groove separating 

 branchial and cardiac regions. 



Braiwhiostegal spine. — Spine on anterior edge 

 of carapace, or near it, immediately below 

 branchiostegal groove (fig. 2). 



Branchiostegite. — Part of carapace not coa- 

 lesced ventrally with the thoracic somites, but 

 overhanging on each side as a covering for cham- 

 ber in which the gills are concealed. 



Buccal cavity. — Cavity on ventral surface of 

 body in which the mouthparts are situated; it is 

 bounded anteriorly by the epistome, laterally by 

 the free edges of the carapace. 



Carina. — A keellike ridge or prominence. 



Carpus (carpopodife). — Third article from the 

 distal end of a leg. 



Cervical groove. — Complex groove or series of 

 grooves running across carapace. It is transverse 

 at the middle, then turns obliquely forward (and 

 outward in brachyurans) to the anterolateral 

 margin. 



Chela. — Arrangement of the distal two articles 

 of a crustacean limb by which the terminal ele- 

 ment is opposed to the element which precedes it, 

 so that the appendage is adapted for grasping. 



In a true chela, the elements are shaped as 

 lingers which close against each other. 



In a subchela, the terminal article (dactyl) 

 usually closes against the distal surface of the 

 penultimate article (propodus). 



('In lipids. — Pair or pairs of thoracic legs im- 

 mediately behind the maxillipeds. They bear 

 chelae, or pincer-claws, and are often stouter, 

 sometimes much stouter, than the succeeding walk- 

 ing legs. 



Co.ru (coxopodite) .- First or proximal article 

 of a leg or maxilliped. 



Dactyl (dactylus or dactylopodite) . — Terminal 

 or distal article of a leg or maxilliped. The dactyl 

 is the movable finger of a cheliped. 



Efferent channels. — Channels through which 

 water passes from the gills. These open at the 

 sides of the endostome, except in the superfamily 



Oxystomata in which they open at the middle of 

 the endostome. 



Endognath. — Inner or principal branch of a 

 maxilliped. 



Endopodite. — Medial ramus of a biramous ap- 

 pendage. 



Endostome. — Part of the epistome which forms 

 the palate in brachyurans and is usually separated 

 from the epistome proper by a transverse ridge. 



Epibranchial (epibranchial region) . — Portion 

 of the porcellanid (crab) carapace which is situ- 

 ated behind the orbit and above the metabranchial 

 region. The region situated between the cervical 

 groove and the linea anomurica. There is often a 

 strong spine on the region, referred to as the 

 epibranchial spine. 



Epigastric lobes. — Anterior lobes or subregions 

 of the gastric region. 



Epimere. — A lateral part of the wall of body 

 somites situated between the tergum and the in- 

 sertion of appendages. 



Epipodite. — Outgrowth of the first seven 

 thoracic coxae. 



Epistome. — The antennal sternum is mainly 

 represented by the epistome, a plate of varying 

 shape, lying between the labrum and the bases of 

 the antennae. In Natantia the epistome is com- 

 partively narrow, and on each side is separated 

 from the lateral portions of the carapace by the 

 exhalant branchial channels. In most of the Rep- 

 tantia, the epistome is broad and comes in con- 

 tact with the carapace on each side; in the 

 Brachyura, it becomes firmly united with the 

 carapace. In this way, there is defined, more or 

 less distinctly, a buccal frame within which lie 

 the mouth parts, and which in most Brachyura is 

 closed by the operculiform third maxillipeds. The 

 sides of this buccal frame are formed by the free 

 anterolateral margins of the carapace. 



Exognath. — Outer or secondary branch of a 

 maxilliped. 



Exopodite. — Lateral ramus of a biramous 

 appendage. 



Fingers (digits).- Narrow scissorlike blades of 

 the claw end of a cheliped, with the movable linger 

 being the dactyl, and the immovable finger the 

 terminal pari of the propodus. 



Front. — Frontal portion of carapace ; thai por- 

 tion of the carapace of a crab which lies between 

 the orbits. 



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FISH AND WILDLIFE SERVICE 



