45 
Gaetanus miles is easily distinguished from the other species, by the great length of the 
antennules. The antennules are fully twice as long as the entire animal, from the apex of the 
frontal spine to the end of the furca. The frontal spine is very prolonged, and when viewed 
laterally, is seen to taper uniformily from the base to the apex. The spines of the last thoracic 
segment extend beyond the middle of the genital segment. The combined length of the abdomen 
and furea, is slightly less than one-fourth of the total length of the cephalothorax, from the 
apex of the cephalic spine to the base of the genital segment. The rostrum is slightly bifid 
at the apex. The lamella on the basal joint of the second maxillipedes, has a bluntly rounded 
apex, and a very slight excavation. The exopodite of the first pair of feet is two-jointed, with 
a very faint line across the middle of the first joint. The first joint of the basiopodite of the 
fourth pair of feet, is furnished with about twelve strong short spines on its inner distal angle. 
Seven specimens, all females, were found. Length 4,3 mm. 
This species has been recorded from the Atlantic and Pacific Oceans. G. P. Farran 
has met with it in the deep water plankton taken off the West Coast of Ireland. 
The ‘Siboga’ specimens of this Gaetanus, appear to differ slightly from GrtESBRECHT’s 
type, in their larger size, and in possessing twelve instead of six spines on the inner margin 
of the first basal joint of the fourth feet. 
2. Gaetanus armiger Giesbrecht. Plate VIII, figs. 16—22. 
Gaetanus armiger Giesbrecht, 1888, p. 335. 
Gaetanus armiger Giesbrecht, 1893, p. 219, pls. 14 & 36. 
Gaetanus armiger T. Scott, 1893, p. 71, pl. 8, figs. 16—27. 
Gaetanus armiger I. C. Thompson, 1903, p. 17. 
Gaetanus armiger Cleve, 1904, p. IQI. 
Gaetanus armiger Wolfenden, 1904, p. III. 
Gaetanus armiger Sars, 1905(a), p. 4. 
Gaetanus armiger Pearson, 1906, p. 14. 
Gaetanus armiger van Breemen, 1908, p. 39, fig. 44. 
This species appeared to be very rare in the ‘Siboga’ plankton and was only noted at 
two stations as shewn. 
Stat. 118, 1 specimen. — Stat. 215%, I specimen. 
Some care is required to identify this Gaetanus, as two species very like it in general 
appearance, have been described within recent years. 
The antennules extend to the anal segment. The frontal spine is very small and can, 
only with difficulty, be observed when the copepod is viewed from the dorsal aspect. The 
spines of the last thoracic segment extend beyond the middle of the genital segment. The 
combined length of the abdomen and furca, is equal to one-third of the total length of the 
cephalothorax, from the apex of the frontal spine to the base of the genital segment. The 
rostrum is small and is distinctly bifid at the apex. I was unable to detect the lamella on the 
basal joint of the second maxillipedes. The exopodite of the first pair of feet is distinctly three- 
jointed. The first joint of the basiopodite of the fourth pair of feet is furnished with a number 
of fine bristles along its inner margin. 
45 
