208 



COPEPODS OF LAST CRUISE OF CARNEGIE 



in the eastern Pacific and a few others in the central part 

 north of the Samoan Islands. It was taken in 2 nocturnal 

 and 2 diurnal surface tows, 6 50-meter tows, and 3 100-meter 

 tows. The Carnegie specimens seemed to prefer the 50-meter 

 depth, and this was the only tow in which they were 

 recorded as abundant. Half the Siboga specimens were ob- 

 tained at the surface, some in the daytime and some at night, 

 and the other half were taken in vertical hauls from con- 

 siderable depths. 



ScolecithricelJa minor (Brady) 

 (Figures 124, 126, 130) 



[Scolccithrix minor Brady, Voyage of H.M.S. Challenger, 

 Zool., vol. 8, pt. 23, Copepoda, p. 58, pi. 16, figs. 15, 16, pi. 

 18, figs. 1-5, 1883.] 



Found at three stations in the Adantic and in widely 

 scattered localities in the Pacific. It was taken in i surface 

 tow, 8 50-meter tows, and 6 loo-meter tows. These few 

 specimens showed a preference for the 50-meter depth and 

 gave no evidence as to nocturnal migration. This species has 

 been reported from the North and South Atlantic and the 

 Indian Ocean, but this is the first record from the Pacific 

 Ocean. 



Scolecithricella ovata (Farran) 

 (Figure 125) 



[Scolccithrix oi'iUa Farran, Ann. Rept. Fisheries, Ireland, 1902- 

 03, pt. 2, app. 2, p. 37, pi. 6, figs. 13-18; pi. 7, figs. 1-7, 

 1905.] 



A few specimens were found in the loo-meter tow at 

 station 9 in the northern Atlantic, southwest of Iceland, and 

 this was the only record for the cruise. The species was re- 

 ported from the same locality by With (1915, p. 208), and 

 Farran's (1905, p. 37) original specimens came from the 

 west coast of Ireland. Pearson (1906, p. 18) gave the vertical 

 range as 382 fathoms, which makes it a deep-water species 

 not likely to be obtained in the upper 100 meters. This seems 

 to be a typical Atlantic species and has not as yet been found 

 anywhere else. 



Scolecithricella porrecta (Giesbrecht) 

 (Figures 127, 134) 



[Scolccithrix porrecta Giesbrecht, Atti R. Accad. Lincei, Rome, 

 ser. 4, vol. 4, sem. 2, p. 338, 18S8; Fauna und Flora des 

 Golfes von Neapel, v(j1. ig, pp. 2(16, 285, pi. 13, figs. 6, 41; 

 pi. 37, fig. II, 1892.] 



Not found in the Atlantic plankton, and in the Pacific 

 confined chiefly to the region north of 40° north latitude. It 

 was taken in 3 50-meter tows and 5 100-meter tows, but was 

 not found at the surface either by day or by night. The 

 female is distinguished by the exceptionally long spine on 

 the inner margin of the fifth legs. Giesbrecht's (1888, p. 338; 

 1892, p. 266) original specimens, on which the species was 

 founded, came from the eastern Pacific just south of the 

 ec]uator, at a depth of 1800 meters, and it has not been re- 

 ported trom any other locality. 



Scolecithricella spinacantha, new species 

 (Figures 103- loS) 



Occurrence. A few females were found in the 50-meter 

 tows at stations 158 and 159, just north of the Samoan 

 Islands in the tropical Pacific. In company with the adults 

 were some juveniles which had not developed beyond the 

 early copepodid stages, and lacked the fifth legs. 



Description of female. Metasome elongate -ovate, strongly 

 narrowed anteriorly and more bluntly rounded posteriorly. 

 Head fused with first segment and the two nearly one-half 

 longer than the free thorax and widest across the posterior 

 margin. Fifth segment also fused with fourth, its posterior 

 corners bluntly rounded and projecting slightly backward. 

 Urosome about one-fifth as wide and one-fourth as long as 

 metasome and four-segmented. The genital segment is a 

 little less than half the length of the urosome and slightly 

 wider than the abdomen, with nearly straight sides. The 

 three abdominal segments are about equal in length but 

 diminish in width posteriorly; the anal segment is somewhat 

 triangular, longest on the mid-line and considerably short- 

 ened on the lateral margins, leaving the posterior corners 

 obliquely truncated. The caudal rami are about as wide as 

 long, and divergent, each with four long setae, the second 

 inner one longer than the entire urosome. 



The rostrum is composed of two short, stout filaments 

 attached to a projection on the forehead, with no cilia 

 visible at their tips. The first antennae are slender and 

 reach to about the middle of the abdomen; the second an- 

 tennae and mouth parts are similar to those of other species 

 of the genus except that the teeth on the chewing blade of 

 the mandibles are longer, more slender, and very unequal 

 in length. They resemble needles or attenuated spines far 

 more than they do ordinary teeth. 



The first four pairs of swimming legs have three-segmented 

 exopods, and the endopods are one-, two-, three-, and three- 

 segmented respectively. The first and fourth legs have no 

 spines on their posterior surfaces that can be detected, but 

 the second and third legs are covered rather sparsely on the 

 posterior surface with small spines not definitely arranged. 

 The fifth legs are very characteristic and give rise to the 

 specific name; each consists of a single segment and a basal 

 part. The segment is tipped with a short and stout conical 

 spine, inside the base of which at the inner distal corner is 

 another stout spine five or six times as long as the terminal 

 one, with a row of short cilia along its dorsolateral surface. 

 On the outer margin of the segment, just beyond its center, 

 is a large projecting lobe, which, together with the distal 

 outer margin of the segment itself, is fringed with coarse, 

 flattened spines. The distal margin of the lobe, as it curves 

 around to join the side of the segment, forms a sort of sinus 

 which strongly suggests that the segment is really made up 

 of two segments fused. But a careful examination gave no 

 evidence of division on either surface of the leg or in the 

 arrangement of the inner musculature. 



Total length, 1.05 mm; length of metasome, 0.87 mm; 

 width, 0.42 mm. 



Type. U. S. Nat. Mus. no. 64005. 



