COPEPODS OF THE WOODS HOLE REGION 



399 



.^?^^. 



3. Posterior margin of genital segment convex, leg rudiments 



scarcely reaching the abdomen curtus (p. 399) 



Posterior margin of genital segment concave, leg rudiments 



reaching middle of abdomen balistae (p. 400) 



4. The 2 abdominal segments about same length ; genital segment 



widest near posterior end bonito (p. 407) 



Terminal abdominal segment three times as long as basal ; gen- 

 ital segment widest at its center rufimaculatus (p. 402) 



5. Genital segment widest near posterior end, with a pair of leg 



rudiments on lateral margins schistonyx (p. 401) 



Genital segment widest at its center, without leg rudiments rapax (p. 403) 



CALIGUS CURTUS Muller 



Figure 245 



Callgus curtus MtJLLEK, Entomostraca, p. 130, pi. 21, fig. 1, 1785. — Wilson, Proc. 

 U. S. Nat. Mus., vol. 28, p. 578, pi. 10, 1905. 



Occwrence. — Found at Woods Hole on the outside surface of the 

 cod, hake, haddock, pollack, halibut, and barn-door skate. 



Distribution. — English seas (T. Scott, Baird, Norman, Brady) ; 

 North Sea (Timm, Hansen) ; coast of Belgium (Beneden) ; Kattegat 

 and Skager Kak (Olsson) ; coast of Greenland (Fabricius, Strom) ; 

 Mediterranean (Brian) ; off Long Island (Pickering and Dana) ; 

 Vineyard Sound (Smith, Rathbun) ; 

 coast of Ireland (Pearson) ; coast of 

 Norway (Rathke, Olsson). 



Color. — Body a uniform yellowish 

 horn color, marked in older individ- 

 uals by dendritic spots of ochre- 

 yellow; eye reddish. 



Female. — Carapace more than half 

 the entire length, widest behind the 

 center; lunules large and circular; 

 genital segment oblong, with parallel 

 sides and rounded corners; abdomen 

 nearly as wide as long, less than half 

 the length of the genital segment; 

 caudal rami short and curved in- 

 ward; furca the shape of the letter H. Fourth legs 3-segmented, with 

 four spines and a seta, the inner terminal spine much the longest 

 and dentate ; fifth leg rudiments minute and invisible dorsally. Total 

 length, 8-12 mm. 



Male. — Much larger than female; carapace ovate, as wide as long; 

 genital segment orbicular, wider than long, with convex lateral mar- 

 gins; abdomen 1-segmented, and without the caudal rami distinctly 

 shorter than the genital segment; caudal rami inclined inward and 

 touching at their tips. Second antenna with a rasplike pad on 



Figure 245. — Caligus curtus: a. Fe- 

 male, dorsal ; b, female, fourth leg 



