WILLIAMS: CRABS OF THE GENUS CALLIXECTES 



which in turn is connected to oviduct and ovary, 

 but it is the gonopore alone that shows crude 

 structural specificity. Hartnoll ( 1968) showed that 

 the gonopore of portunids is an uncovered struc- 

 ture often rounded laterally and pointed mesially, 

 whose margin is the "rigid integument of the ster- 

 num, while the lumen is normally blocked by 

 bulges of the flexible integument which comprises 

 the lining of the vagina." In the set of species 

 having males with long first gonopods, the gono- 

 pores of females are paraboloid in outline (Figures 

 22i-l, 23a-c). Parallels with the other two sets of 

 male gonopod types are less pronounced. Of the 

 intermediate second set, female C. arcuatus and 

 danae have asymmetrically ovoid gonopores (Fig- 

 ure 22e, f); exasperatus has an elongate sinuous 

 gonopore with shelflike overgrowth on the 

 cephalic border (Figure 22g), and hellicosus fits 

 into this group (Figure 22h). Females correspond- 

 ing to the set of males with short first gonopods 



have gonopores varying from broadly open 

 paraboloid in C. ornatus (Figure 22d) to increas- 

 ingly narrowed openings in C. gladiator and mar- 

 ginatus (Figure 22b, c), culminating in the narrow 

 transverse slit of C. similis (Figure 22a). 



MEASUREMENTS 



The foregoing discussion shows that measure- 

 ments must be taken from adults if they are to 

 have systematic usefulness because the young are 

 proportionally different from adults as well as 

 being incomplete for secondary sexual characters. 

 Some species are larger than others and certain 

 proportions are considered useful in keys for 

 identification (Rathbun, 1930; Garth and 

 Stephenson, 1966). Certain populations within 

 species may deviate from the "typical." Initially I 

 thought that analysis of morphometric characters 

 might help to define differences among species as 

 well as among populations within species. 



Figure 1 . — Mature male Callinectes sapidus from North Carolina in dorsal view ( x 1 ). Measured features indicated by numbered lines: 

 1, length; 2, width to base of lateral spines; 3, width including lateral spines; dimensions of metagastric area — a, anterior width, b, 

 length, c, posterior width. Other features included in descriptions: (carapace) F, frontal teeth; O, outer orbital tooth; AL, anterolateral 

 teeth; LS, lateral spine; PL, posterolateral margin; EP, epibranchial line; ES, epistomial spine; MB, mesobranchial area; CA, cardiac 

 area; BL, branchial lobe; (cheliped) M, merus; C, carpus; P, propodus; D, dactyl. 



689 



