434 MESSES, T. AND A. SCOTT— liEVlSlOJN' OF THE BEITISH COPEPODA 



EcTiNOSOMA MELANiCEPS, Boeck (1864). (PL 36. figs. 13, 28, 45 ; PI. 37. figs. 11, 22, 

 40, 49 ; PL 38. figs. 2, 21, 41, 4G.) 



1864. Ectinosoma melaniceps, Boeck (i), p. 30. 



1880. Ectinosoma melaniceps, Brady (3), vol. ii. p. 11, pL xl. figs. 17-20. 



1890. Ectinosoma melaniceps, T. Scott (13), p. 318. 



1893. Ectinosoma melaniceps, I. C. Tliompsou (16), p. 18, pi. xxi. fig. 2 a. 



Description. Length -63 mm. [-}q of an inch). Eostrum elongate, slender, ciu'ved 

 downward. 



Antennules short, 7-jointed, gradually tapering from the moderately stout base to 

 the slender apex ; the third joint is considerably longer than any of the other joints, as 

 exhibited by the formula, which shows the proportional lengths uearly of all the joints: — 



No. of the ioints : 1 . 2 . 3 . 4 . 5 . G . 7 



Proportional lengths : 9 6114552 



Antennae elongate ; basal joint stout and equal to about two-thirds the length of the 

 next one; the second and third joints are more slender than the basal joint, and the 

 last is somewhat shorter than the preceding one ; the secondary branch has the middle 

 joint very small, while the first and third are comparatively elongate (PL 37. fig. 11). 



Moitth-organs nearly as in Ectinosoma Sarsi, but much smaller (PL 37. figs. 22, 40, 49). 



The outer branches of the first pair of swimming-feet are equal to about three fourths 

 the lengtii of the inner branches ; the first and second joints only of the outer branches 

 are furnished witli elongate spines, and the interior marginal setae of both branches are 

 slender and not plumose ; in the fourth pair tlie outer and inner branches are about 

 equal in length (PL 38. figs. 2 and 21). 



The produced inner portion of the basal joint of the fifth pair, which is cylindrical in 

 outline and reaches only a little beyond the middle of the secondary joints, is provided 

 with a moderately long apical seta and stout conical spine serrate on the edges, while 

 the secondary joint bears one slender and three spiniform apical setae, the second one 

 from inside being very long with a tenuated extremity (PL 38. fig. 41). 



Caudal stylets very short (PL 38. fig. 46). 



Habitat. Generally distributed, and usually among weeds, in the laminarian zone. 



Memarks. This species is readily distinguished by its having a considerable portion of 

 the front part of the head of a dusky colour, as well as by the structure of the 

 antenniiles and fifth pair of feet. 



Ectinosoma armiferom, sp. n. (PL 36. figs. 20 and 43; PL 37. figs. 4, 17, 31, 53; 

 PL 38. figs. 14, 19, 37, 43.) 



Description. Length -97 mm. {-.h^ of an inch). Body stout; rostrum prominent 

 (PL 36. fig. 20). 



Antennules 5= (?or 6-) jointed, very short and robust, strongly setiferous, especially 

 towards tlie distal end, where there are several strong and very elongate plumose setae 



