DECAPOD CRUSTACEANS OF THE WEST INDIES 225 



Carapace (Car). The "head shield" covering the cephalothoracic somites of the 



body. 

 Cardiac region (Card). The dorsomedian area on the carapace bounded anteriorly 



by the gastric region, laterally by the branchial regions, and (in the crabs) 



posteriorly by the intestinal region. This area is often very narrow in the 



crayfishes and is commonly called the areola. 

 Carpus, pi. carpi (Crp). The fifth segment from the proximal end of a typically 



7-segmented appendage. 

 Cephalothorax. The fused anterior part of the body bearing all of the appendages 



except the pleopods and uropods. 

 Cervical groove (cvg). A groove or series of grooves sometimes present on the 



carapace; it is mesially transverse, laterally oblique, and separates the 



gastric and hepatic regions from the cardiac and branchial regions. 

 Chela, pi. chelae. A pincer formed by the two distal podomeres of a pereiopod 



in which the movable finger or dactyl opposes a fixed finger formed by a 



distal extension of the propodus. 

 Cheliped. A pereiopod bearing a chela. 



Congener. A species belonging to the same genus as another. 

 Cornea (Crn). The faceted portion of the eye. 

 Coxa, pi. coxae (Cx). The first or proximal segment of a typically 7-segmented 



appendage. 

 Dactyl (Dct). The seventh or terminal segment of a typically 7-segmented 



appendage. 

 Endopod (End). The mesial branch of a bifurcate appendage, especially one 



arising from the protopodite of the pleopod of shrimps. 

 Epibranchial region (epBr). The anterior part of the branchial region on the 



carapace of crabs. 

 Epigastric lobe (epGst). A paired anterior boss on the gastric region of the 



carapace of crabs. 

 Epigean. Living on the surface of the earth, as opposed to spelean. 

 Epistome (Epst). The transverse plate anterior to the mouth area in crayfishes 



and crabs. 

 Exopod (Exp). The lateral branch of a bifurcate appendage arising from the 



basis or from the protopodite. 

 Extensor margin. The outer or longer margin of a flexed appendage. 

 Eyestalk (Eyst). The peduncle or unfaceted portion of the eye supporting the 



cornea. 

 Finger (Fgr). One of the terminal elements forming the pincers of a chela, the 



movable finger being the dactyl and the immovable finger the terminal 



extension of the propodus. 

 First form male. The breeding form of male crayfishes in which one of the terminal 



projections of the first pleopod is corneous, as opposed to the second form 



male in which this projection is not corneous. 

 Flagellum, pi. -la (Fig). The multiarticulate, usually whiplike terminal portion 



of an antennule or antenna. 

 Flexor margin. The inner or shorter margin of a flexed appendage. 

 Front (Ft). The margin of that portion of the carapace of crabs lying between 



the orbits; often used interchangeably with frontal region. 

 Frontal region (Ftl). The anterior area of the carapace lying between the orbits 



and bounded posteriorly by the gastric region. 

 Fronto-orbital distance. The interval between the outer orbital angles of crabs. 



