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I do not think the first joint of the basiopodite of the fourth pair of feet would possess the 

 armature described by Canu. The three-jointed exopodite of the tirst pair of feet in Gaetanus 

 caudani, is the only noteworthy difference between that species, and the form now dealt with. 

 The three-jointed exopodite might easily be changed, and the rudimentary fifth pair of feet be 

 suppressed at the final ecdysis. 



I regard Farrax's Gaetanus pileatus to be identical with Canu's Gaetanus caudani. 

 Farrax's type specimen was obtained from the stomach of a mackerel, and even a very short 

 exposure to the gastric juices would bring about some changes in the appearance of the 

 copepod. The only difference between Farrax's figures and those now given, appears to be in 

 the setting of the cephalic spine, and this is probably due to the cause mentioned. Some weight 

 is given to the view that Gaetanus pileatus is the same as Gaetanus caudani by the fact that 

 Oöthrix öidentata Farran (1905), is identical with Neoscolecithrix kochleri Canu (1896), and 

 both these copepods have been taken in some quantity, in the plankton collected from the 

 deep water of the Faröe Channel, by the Scottish International Fisheries Cruiser 'Goldseeker'. 

 I have compared the Faröe Channel form of long spined Gaetanus with Gaetanus caudani of 

 this report, and can find no difference between them. 



Esterly's Gaetanus unicornis is, I think, clearly identical with Gaetanus caudani Canu. 



Gaetanus caudani has apparently a wide distribution, extending from the deep water of 

 the Malay Archipelago to the Faröe Channel. 



4. Gaetanus minor Farran. Plate IX, flgs. 1 — 8. 



Gaetanus minor Farran, 1905, p. 34, pi. V, figs. 1 — 11. 



Gaetanus minor Pearson, 1906, p. 14. 



Gaetanus minor Farran, 1908, p. 37. 



Gaetanus minor van Breemen, 1908, p. 41, fig. 46. 



This Gaetanus was obtained from plankton collected with the Hexsex vertical net at 



the following two stations. 



Stat. 141 (1500 metres to surface). — Stat. 276. (750 metres to surface). 



Gaetanus minor is not unlike a small form of Gaetanus armiger, and without careful 

 examination, may be easily overlooked. 



The antennules reach to the middle of the abdomen. The cephalic spine is somewhat 

 similar to that of Gaetanus armiger, but it is distinctly longer and more conspicuous when 

 viewed from the dorsal surface. The spines of the last thoracic segment extend nearly to the 

 end of the genital segment. The combined leng-th of the abdomen and furca, is contained about 

 three and a half times in the total length of the ceplialothora.w from the apex of the cephalic 

 spine to the base of the genital segment. The genital segment slightly exceeds the combined 

 length of the second and third segments. The rostrum is small and does not appear to be 

 divided at the apex. The lamella on the basal joint of the second maxillipedes is bluntly rounded 

 at the apex and slightly excavated. The exopodite of the first pair of feet is two-jointed, with 

 no tracé of a division across the first joint. The first joint of the basiopodite of the fourth pair 

 of feet, is furnished with a very few bristles on its inner margin. 



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