COPEPODS GATHERED BY ALBATROSS—WILSON 179 
original lack of data was no doubt due to the fact that the original 
specimen, like the Albatross specimens, was captured while swimming 
freely in the plankton. 
CALIGUS RAPAX Milne Edwards 
Caligus rapar MILNE Epwarbs, Hist. nat. Crust., vol. 8, p. 453, pl. 38, 1840. 
Station 2396. At this station in the Gulf of Mexico a single male 
believed to be this species was taken in a surface tow. The species is 
parasitic upon a great variety of hosts without showing particular 
preference for any of them. Both sexes have been reported many 
times as captured while swimming freely among the pelagic forms. 
CALIGUS THYMNI Dana 
PLATE 22, FIGURE 317 
Caligus thymni DANA, Proc. Amer. Acad. Arts and Sci., vol. 2, p. 56, 1849; United 
States Exploring Expedition, 1838-1842 (Wilkes), vol. 14, pt. 2, Crustacea, 
p. 1358, 1853 ; pl. 94, fig. 3 a-c, 1855. 
Caldera Bay anchorage, west coast of Mindanao, Philippine Is- 
lands. The tow at this anchorage was made by setting the net in 
the tide current at the gangway; many copepods were obtained. 
Among them was the male of a species described as new by Dana in 
the Wilkes plankton and named Caligus thymni. His figures in- 
cluded a ventral view of the male and a dorsal view of the genital 
segment, abdomen, and ovisacs of the female. The only full length 
dorsal view of either sex was one of the male published by T. Scott 
(1894, p. 129) which did not show the markings on the dorsal surface 
of the carapace. Accordingly, figure 317 is here included in order to 
call attention to certain important characters. 
The carapace forms two-thirds of the entire length and is three- 
fourths as wide as long. On the dorsal surface the transverse groove 
is in front of the center, and the lateral grooves are pushed well over 
toward the sides, thereby making the area included by them excep- 
tionally large. The genital segment is one-half wider than long, with 
convex lateral margins and two pairs of rudimentary legs on the 
posterior margin. The caudal rami are less than half as long as the 
anal segment and are wider than long, each with four setae. For 
ready reference this male has been given U.S.N.M. No. 74118. 
Genus CALOCALANUS Giesbrecht, 1888 
CALOCALANUS PAVO (Dana) 
Calanus pavo Dana, Proc. Amer. Acad. Arts and Sci., vol. 2, p. 18, 1849; United 
States Exploring Expedition, 1838-1842 (Wilkes), vol. 14, pt. 2, Crustacea, 
p. 1061, 1853; pl. 72, fig. 12 a, b, 1855. 
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