Setella gracilis Brady, 1883, p. 10S, pi. L, figs. 1 — 10. 



Setella gracilis Giesbrecht, 1893, p. 559, pis. 1 & 43. 



Setella gracilis T. Scott, 1893, p. 109. 



Setella gracilis I. C. Thompson, 1900, p. 285. 



Setella gracilis Wheeler, 1900, p. 188, fig. 24. 



Setella gracilis Cleve, 1901, p. 9. 



Setella gracilis A. Scott, 1902, p. 409. 



Setella gracilis I. C. Thompson, 1903, p. 33. 



Setella gracilis Thompson & Scott, 1903, p. 257. 



Setella gracilis Cleve, 1903, p. 368. 



Setella gracilis Wolfenden, 1905 (a), p. 1030. 



Setella gracilis van Breemen, 1908, p. 178, fig. 192. 



Males and females belonging to this characteristic form were obtained from the plankton 

 collected at the following stations. 



Stat. 19. — Stat. 35. — Stat. 36. — Stat. ^y. - - Stat. 40. -- Stat. 47 b . — Stat. 50. - 

 Stat. 66. — Stat. 75 (11 metres to surface). — Stat. 81. — Stat. 96 (night). — Stat. 98. - 

 Stat. 99. — Stat. 110. -- Stat. 118 (900 metres to surface). — Stat. 121. -- Stat. 124. — 

 Stat. 128 (700 metres to surface). — Stat. 138. — Stat. 143 (1000 metres to surface). — 

 Stat. 146. — Stat. 148 (1000 metres to surface). — Stat. 168. — Stat. 213. — Stat. 216. — 

 Stat. 217. — Stat. 304. — Stat. 315. 



Macroselella gracilis appears to be an entirely pelagic species and has a moderately 

 wide distribution in the warm regions of the great oceans. 



38. Family Clytemnestridae nov. 



The body is rather slender and depressed. The distal ends of the cephalic and first 

 three thoracic segments are considerably expanded and pointed. The thoracic segments are 

 produced posteriorly. The cephalic segment is large and triangular in outline when seen from 

 above, and is furnished with a blunt pointed rostrum. The antennules are eight-jointed. The 

 exopodite of the antennae is short and one-jointed. The mandibles, maxillae and first pair 

 of maxillipedes are very rudimentary. The second pair of maxillipedes is well developed and 

 prehensile. The exopodite of the first pair of feet is composed of a single joint. The endopodite 

 is three-jointed and much longer than the exopodite. The exopodites and endopodites of the 

 second, third and fourth pairs of feet are three-jointed. The fifth pair of feet is slender and 

 two-jointed. The female carries a single ovisac. 



This family is established for the reception of the genus Clylcmnestra Dana. It differs 

 very considerably from any of the other Harpacticoida in the long-jointed prehensile second 

 pair of maxillipedes, and in the structure of the first pair of feet. 



Genus Clytemnestra Dana, 1852. 



The members of this genus are easily recognised by the form of the body, by the 

 pointed cephalic and thoracic segments, and by the structure of the various appendages. 



23 1 



