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PROCEEDINGS OF THE NATIONAL MUSEUM 



Fourth thoracic leg uniramous, three-segmented. Protopodite one- 

 segmented, equal to combined lengths of two segments of exopodite; 

 middle of proximal surface projecting slightly in irregularly shaped 

 articular surface. Protopodite with two setules projecting from outer 

 margin and one plumose seta from outer distal surface. First segment 

 of exopodite about two-thirds length of second, with single, membrane- 

 margined spine at outer distal corner; base of spine ringed with frilled 

 margin. Second segment with three spines from distal surface, one 

 from outer lateral margin. Spine on outer margin with membrane 

 on both outer and inner margins, base fringed with frilled margin. 

 Inner terminal spine elongate, twice length of next longest spine, 

 slightly curved at tip. Outer spine shortest of three, with fine mem- 

 brane along outer and inner margins. All thi-ee terminal spines with 

 bases rimmed by frilled margin (fig. 3/). 



Caudal rami slightly wider than long, length approximately one- 

 third length of second abdominal segment ; row of setules present along 

 inner margin. Caudal rami with five plumose setae: short seta on 

 outer distal corner, short seta on inner distal corner, and three long 

 setae from middle of distal margin. 



The character of the armament of the thoracic legs is given below 

 (for explanation of symbols, see figure 1): 



Remarks. — Except for some minor differences in the armature of 

 the thoracic legs, Caligus kala, C. kuroshio Shiino, 1959, and C. bonito 

 Wilson, 1905, have the same thoracic leg makeup. Shiino (1959a) 

 has indicated that C kuroshio differs from C. bonito by a series of 

 minor characteristics such as the position of the accessory lappet on 

 the maxilla and the length relationships of the body parts with other 

 parts. Basically, however, both species are similar. C. kala differs 



