176 



COPEPODS OF LAST CRUISE OF CARNEGIE 



Genus CANTHOCALANUS A. Scoit, 1909 



Canthocalaiius pauper (Cjiesbrecht) 



[Cnlaiiiis pauper Giesbrecht, Atti R. Accad. Lincei, Rome, ser. 

 4, vol. 4, sem. 2, p. 331, 1888; Fauna unci Flora des Golfes 

 von Neapel, vol. 19, pp. gi, 129, pi. 6, fig. 4; pi. 8, fig. 25, 

 1892.] 



Not present in the Atlantic plankton but well scattered 

 over the Pacific, with, however, five large gaps in its distribu- 

 tion, one each in the northern, eastern, southern, central, and 

 western regions. It was taken in 5 nocturnal and 20 diurnal 

 surface tows, 33 50-meter tows, and 30 100-meter tows. These 

 records indicate more or less indifference to light, and this 

 conclusion is supported by the fact that the species was 

 found equally distributed in all three tows at the same time, 

 or in two of them. On the other hand, it was found more 

 often in the two deeper tows during the day, and probably 

 becomes negative as the intensity of the light increases. It is 

 worthy of note that this species was captured only in surface 

 tows during the Siboga expedition and not in any of the ver- 

 tical tows from different depths. 



Genus CARNEGIELLA, new genus 



Body of typical cyclops form, metasome five times as wide 

 as urosome, considerably swollen dorsally and ventrally. First 

 antennae slender, six-segmented, the terminal segment linear 

 and four times as long as the rest of the antenna. Second 

 antenna uniramose and five-segmented; maxillipeds chelate; 

 rami of first four pairs of legs three-segmented; fifth legs 

 lacking in the female; male unknown. 



Genotype. Carnegiella gracilis (Cyclopoida). 



Carnegiella gracilis, new species 

 (Figures 20-25) 



Occurrence. A single female was found in the loo-meter 

 tow at station 151 north of Samoa in the central Pacific. 



Description of female. Metasome pyriform, a little more 

 than twice as long as wide, widest at the center and strongly 

 narrowed anteriorly and posteriorly. Head fused with the 

 first thoracic segment and much longer than the free thorax. 

 Urosome six-segmented, much narrower than fourth segment 

 of metasome, about same width throughout. Genital segment 

 longer but scarcely wider than any of the abdominal seg- 

 ments; the latter all of about the same length and width 

 except the anal segment, which is widened posteriorly. 

 Caudal rami longer than the anal segment and pointed pos- 

 teriorly, where each is armed with three setae, one on the 

 outer and two on the inner margin. Between the setae the 

 lamina of the ramus projects backward and ends in two 

 processes, the outer one longer than the inner and tipped 

 with a hair. 



The first antennae are six-jointed, the five basal joints 

 moderately swollen and tapering distally. The terminal seg- 

 ment is linear and four times as long as the other five seg- 

 ments combined. The fourth segment carries an aesthetask 

 which is linear and closely appressed to the terminal seg- 

 ment, and reaches slightly beyond the tip of the latter. The 



second, third, and fourth segments are setose, but the long 

 terminal segment is naked except for a tuft of setae at its 

 very tip. 



The second antennae are uniramose, slender, and five- 

 segmented, the third segment the longest and the fourth 

 segment the shortest. The basal segment carries a small seta 

 on its inner margin, the fourth segment has a similar one 

 on its outer margin at the distal corner, and the terminal 

 segment is tipped with a single larger seta. The mandibles 

 and maxillae were not removed for examination, as this 

 would have destroyed the solitary specimen. The maxillipeds 

 are two-segmented, rather stout, with a chela at the tip of 

 the second segment. 



The first four pairs of legs are biramose and each ramus 

 is three-segmented; the armature of these legs is very 

 peculiar, as can be seen from figures 24 and 25. In the first 

 and second legs the spines on the outer margins of the 

 exopods are arranged i, i, 2 and are normally developed. In 

 the third and fourth legs the spine on the basal segment is 

 reduced to a tiny rudiment, the one on the middle segment 

 is somewhat better developed, and there is but one on the 

 end segment at the distal corner. The first endopod carries 

 on the outer margin of each of its three segments a single 

 seta; on the inner margins there are one, two, and three setae 

 respectively, and two more at the tip of the third segment, 

 eleven in all, which is an e.xceptionally large number for a 

 first endopod. The third and fourth endopods have no setae 

 on the outer margin, and on the inner margin there are one, 

 two, and two respectively on the three segments, with a 

 single seta at the end of the third segment, six in all. 



Total length, 1.25 mm; length of metasome, 0.85 mm; 

 length of urosome, 0.45 mm. 



Type. U. S. Nat. Mus. no. 64002. 



Remarf{s. This species is distinguished by the exceptional 

 length and linearity of the last segment of the first antennae, 

 by the structure of the maxillipeds and the caudal rami, and 

 by the armature of the swimming legs. 



Genus CENTRAUGAPTILUS G. O. Sars, 1920 



Centraugaptilus rattrayi (T. Scott) 



[Augaptihis rattrayi T. Scott, Trans. Linn. Soc. London, ser. 2, 

 Zoo!., vol. 6, pt. I, p. 36, pi. 2, figs. 25-37, ■^94-1 



A few badly preserved specimens of this species were ob- 

 tained in the loo-meter tow at station 23 in the tropical 

 Atlantic. It was first described by T. Scott (1894, p. 36) as 

 from the Gulf of Guinea, but was afterward reported from 

 various localities in the North Atlantic by Farran (i 908/1, 

 p. 78) and Sars (1925, p. 304). 



Genus CENTROPAGES Kr0yer, 1849 



This genus was well distributed in both oceans except in 

 the northern parts and the southern part of the Pacific, and 

 was more abundant in the tropics. Although most of the 

 species are pelagic in habitat, some of them come close to 

 shore and even enter the mouths of rivers and harbors. Sec 

 chart 5, on following page. 



