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joint is furnished with two short stout spines. The exopodites and cndopodites of the second, 

 third and fourth pairs of feet are three-jointed. The fifth pair is very small, foliaceous and 

 one-jointed. 



One species belonging to this genus was represented in the plankton collected by the 

 'Siboga' in the Malay Archipelago. 



i. Ilyopsyllus affinis T. Scott. 



Ilyopsyllus affinis T. Scott, 1893, p. 101, pi. XI, figs. 4 — 17. 

 Ilyopsyllus affinis A. Scott, 1902, p. 417. 

 Ilyopsyllus affinis Thompson & Scott, 1903, p. 275. 



Five males and one female identical with the above species were found in the plankton 



collected at the following stations. 



Stat. 19, 2 males. — Stat. 89, 1 male. — Stat. 213, 1 female and 2 males. 



Ilyopsyllus affinis is closely related to Ilyopsyllus coriaceus Brady and Robertson, but 

 the female can readily be distinguished by the non-spathuiate character of the principal seta 

 on the furcal joints. 



This species has been recorded from the Gulf of Guinea, the Gulf of Suez, and from 

 the coast of Ceylon. 



36. Family Tachidiidae. 

 Genus Euterpina Norman, 1903. 



The only known member of the genus is readily recognised by the slender arched 

 body, by the prominent sharp pointed rostrum, by the long slender second pair of maxillipedes, 

 and by the one-jointed foliaceous fifth pair of feet. 



This o-enus was represented in the plankton collected by the 'Siboga' in the Malay 

 Archipelago. 



1 . Etitcrpina acutifrous (Dana). 



Harpacticus acutifrous Dana, 1847, p. 153. 



Harpactuus acutifrous Dana, 1S52, p. 1192, pi. 83, fig. 1 1 a— b. 



Euterpe gracilis Claus, 1S63, p. 110, pi. XIV, figs. 1 — 13. 



Euterpe gracilis Brady, 1880, vol. II, p. 22, pi. XL, figs. 1 — 16. 



Euterpe acutifrous Giesbrecht, 1893, p. 555, pi. 44. 



Euterpe acutifrous, var. armata T. Scott, 1893, p. 93, pi. XII, figs. 14—23. 



Euterpe acutifrous I. C. Thompson, 1896, p. 25. 



Euterpe gracilis Brady, 1899, p. 39. 



Euterpe acutifrous I. C. Thompson, 1900, p. 285. 



Euterpe acutifrous A. Scott, 1902, p. 409. 



Euterpe acutifrous I. C. Thompson, 1903, p. 32. 



Euterpina acutifrous Norman, 1903, p. 368. 



Euterpina acutifrous Thompson & Scott, 1903, p. 258. 



Euterpe acutifrous Cleve, 1903, p. 363. 



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