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6. Euchaeta tennis Esterly. Plate XIX, figs. i — 8. 



Euchaeta tenuis Esterly, 1906, p. 61, pis. IX & X. 



A few specimens of a form which appears to be identical with the above species, were 



found in the plankton collected by the 'Siboga', at the following stations. 



Stat. 117% 1 specimen. — Stat. 141, 2 specimens. — Stat. 143, 1 specimen. — Stat. 148, 

 1 specimen. — Stat. 185, 2 specimens. — Stat. 203 (1500 metres), 2 specimens. — Stat. 

 230, 1 specimen. — Stat. 243, 1 specimen. — Stat. 252, 1 specimen. 



The peculiar projection on the ventral surface of the genital segment, when seen from 

 the side, is the most noteworthy character The outer-edge spine on the second joint of the 

 exopodite of the second pair of feet, extends beyond the apex of the first outer-edge spine on 

 the third joint. The second outer-edge spine on the third joint, reaches almost to the base of 

 the third outer-edge spine. Two minute tubercles are visible at the middle of the dorso-lateral 

 edges of the genital segment, when viewed from above. The second inner seta on the furcal 

 joints is much longer than any of the others. The appendicular seta is very short. The females 

 only were obtained. Length 6,8 mm. 



Eucliaeta tennis was described by Esterly from a single specimen obtained in the Pacific 

 Ocean, and the size is given as 6 mm. 



The species is not unlike Euchaeta grandiremis Giesbrecht, but is easily separated from 

 it by the difference in the proportional lengths of the spines on the exopodite of the second 

 pair of feet. 



7. Euchaeta zvolfcndeni nov. sp. Plate XVII, figs. 1 — 12. 



Euchaeta marina Wolfenden, 1905 (a) pars, p. 1007, pi. C, figs. 7, 8, 10, 11, 17, 18. 



Female — length 2,4 — 2,9 mm. 



This Copepod is very like Euchaeta marina in general appearance, but on close exami- 

 nation can easily be distinguished from it. The last thoracic segment is quite symmetrical when 

 viewed from above. The posterior margin, when seen from the side, appears narrowly rounded. 



The combined length of the abdomen and furca is slightly less than half the total length 

 of the cephalothorax, from the frontal projection to the base of the genital segment. The genital 

 segment is as long as the combined length of the next three segments. The segment is irregular 

 in outline, when viewed from the dorsal aspect. The posterior end of the right side is 

 produced into a moderately large and well defined tubercle. A distinct swelling is visible in 

 the region of the genital opening, when the segment is viewed from the side. The second 

 segment is about half the length of the genital segment, and is equal to the combined length 

 of the third and fourth segments. The appendicular seta is much longer than any of the others. 

 The thoracic and abdominal segments are densely covered with short fine hairs. 



The antennules are twenty-three-jointed and extend to the end of the second abdominal 

 segment. 



The antennae, mandibles, maxillae and maxillipedes, are similar to those of Euchaeta 

 marina. The marginal spines on the two apical setae of the first maxilliped are comparatively long. 

 The first pair of feet is similar to that of Euchaeta marina. 



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