NO. 1404. PARASITIC COPEPODS—CALIGID.E— WILSON. 561 



56. Genital segment rectangular; no lobes; free segment short and wide. 



dakarl (van Beneden, 1892). 

 57. Females, both lifth and sixth legs visible; genital segment acorn-shaped. 



Isoni/x (Steenstrnp and Liitken, 1861), p. 602. 



57. Females, no legs visible on genital segment 58. 



57. Males, fifth legs concealed; genital segment narrow ovate, well lobed; emarginate 



posteriorly cliorinemi ( Kn")yer, 1863) . 



58. (xenital segment oblong, four times as wide as abdomen; no lobes; frontal 



plates projecting viurrayimus (T. Scott, 1894). 



58. (ienital segment elliptical, twice as wide as abdomen; no lobes; free segment 



long, narrow IraclunitA'i (Heller, 1865). 



58. (Ienital segment narrow obovate, well lobe<l; free segment short and ))roa(l. 



teuax (Heller, 1865). 

 58. Genital segment oblong; lobes short, l)lunt; abdomen club-shaped; free seg- 

 ment long, narrow pliip.'tniii (B-Smith, 1898, a). 



CALIGUS RUFIMACULATUS, new species. 



Plate V. 



Female. — Carapace more than half the entire leng-th, elliptical, dis- 

 tinctly longer than wide, and scarcely narrowed anteriorly (tig. 51). 



Frontal plates large and wide, nearly straight along their anterior 

 border, and deeply incised at the center, where may nearly always be 

 found the remains of the frontal tilament projecting from the incision. 

 Lunules large, almost circular, and widely separated, but not project- 

 ing ver^^ much. Posterior sinuses wide and inclined to the central 

 axis, leaving the median lobe more than half the entire width and 

 projecting considerably beyond the lateral lobes. Lateral lobes nar- 

 row and cui'ved inward at the tip. Free thorax segment small and 

 narrow, not distinctly sepai-ated from the genital segment, the divid- 

 ing groove l)eing little more than a notch in either side, just back of 

 the fourth legs. Genital segment obovate, as wide as long, nan-owed 

 anteriorly, with smooth, rounded outlines, and without appendages or 

 setiB visible dorsal l3^ 



Abdomen short and one-jointed, three-fourths the length of the 

 genital segment and al)out twice as long as wide; somewhat swollen at 

 the center into a spindle-shape. Anal laminai large and stout. ^^^ 

 cases nearly as wide as the abdomen and about as long as the carapace, 

 35 or 40 eggs in each. 



Anterior antennae large and stout, the two joints about the san)e 

 length and heavily armed with plumose sette and spines. Posterior 

 antemue rather slender, l)ut long, and with the terminal hook sharply 

 bent near the tip; a short and stout accessory spine present posterior 

 to the basal joint. First maxillae small and nearly straight, with a 

 swollen base. Second maxilhe also nearly straight and about as long 

 as the rostrum; rather stout and ))hmt and considei'ably widened at 

 the base. 



