(570 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxviii. 



maxillipeds; figs. 98, 100-102, First, second, third, and fourth swim- 

 ming legs; fig. 99, One of the plumose setae from the posterior 

 border of the terminal joint of the first legs. All the appendages are 

 from the female. 



Plate IX. Caligus aliuncus, new species. Fig. 103, Dorsal view of female; fig. 104, 

 Second antenna; fig. 105, Second maxilla; fig. 106, Furca; fig. 107, 

 Second maxilliped; fig. 108, First swimming leg; fig. 109, Terminal 

 claw of same enlarged to show its serrated border; figs. 110, 111, Third 

 and fourth swimming legs. 



Plate X. Caligus curtus Midler. Fig. 112, Dorsal view of male; fig. 113, Dorsal view 

 of female; fig. 114, Very young Chalimus, the third thorax segment 

 not fully fused with the head; fig. 115, Fully developed male Chali- 

 mus; fig. 116, First maxilliped; fig. 117, Second maxilliped; fig. 118, 

 Furca; fig. 119, Second swimming leg; fig. 120, First swimming leg; 

 figs. 121, 122, Third and fourth swimming legs; fig. 123, Second 

 antenna of male; fig. 124, Second maxilliped of male. 



Plate XL Caligus chelifer, new species. Fig. 125, Dorsal view of female without egg 

 strings; fig. 126, Dorsal view of female with egg strings, showing 

 difference in shape of genital segment; fig. 127, Second antenna and 

 first maxilla; fig. 128, Second maxilla, showing rudimentary endo- 

 pod; fig. 129, First maxilliped; fig. 130, Terminal claw, or chela, of 

 second maxilliped; fig. 131, Furca; fig. 132, First swimming leg; fig. 

 133, Terminal joint of the same, enlarged; fig. 134, Fourth swim- 

 ming leg. 



Plate XII. Caligus helones Kroyer and Caligus lalifrons, new species. Fig. 135, Caligus 

 belones, dorsal view of female; fig. 136, Second antenna; fig. 137, 

 First and second maxilla?, and furca; figs. 138 and 139, Third and 

 fourth swimming legs; fig. 140, Caligus latifrons, dorsal view of 

 female; fig. 141, Second antenna; fig. 142, Second maxilla; fig. 143, 

 Second maxilliped; fig. 144, Furca; fig. 145, First swimming leg; 

 fig. 146, Terminal joint of same enlarged ; figs. 147-149, Second, third, 

 and fourth swimming legs. 



Plate XIII. Caligus bonito, new species, and Caligus pelamydis Kroyer. Fig. 150, 

 Caligus bonito, dorsal view of female with egg strings; fig. 151, dorsal 

 view of female without egg strings, drawn by Richard Rathbun; fig. 

 152, Dorsal view of male, drawn by Richard Rathbun; fig. 153, Pos- 

 terior part of young female, showing the abdomen segments of about 

 equal length; fig. 154, Caligus pelamydis, dorsal view of female; fig. 

 155, Second antenna; fig. 156, First and second maxillae; fig. 157, 

 Second maxilliped; fig. 158, Furca; figs. 159-161, Second, third, and 

 fourth swimming legs. 



Plate XIV. Caligus productus Dana and Caligus isonyx Steenstrup and Liitken. Fig. 

 161 a, First swimming leg of Caligus pelamydis; fig. 162, Caligus pro- 

 ductus, dorsal view of female; fig. 163, Second antenna; fig. 164, 

 Second maxilla; fig. 165, Furca; fig. 166, Second maxilliped; figs. 

 167-170, First, second, third, and fourth swimming legs; fig. 171, 

 Caligus isonyx, dorsal view of female, after Steenstrup and Liitken. 



Plate XV. North American species of Caligus not in the National Museum collec- 

 tion. Fig. 172, C. balistae, Steenstrup and Liitken, dorsal view of 

 female; fig. 173, idem, Dorsal view of male; fig. 174, Furca; fig. 175, 

 Second maxilliped; figs. 176, 177, Third and fourth swimming legs; 

 fig. 178, C. thymni Dana, ventral view of male; fig. 179, Dorsal view 

 of genital segment and abdomen of female; fig. 180, C. hsemulonis 

 Kroyer, dorsal view of female; fig. 181, idem, Dorsal view of male; 



