FROM THE GULF OF GUINEA. 33 



Hemicalaktjs PLrMOSUS, Claus. (PI. II. fig. 6 ; PI. VI. fig. G.) 



1863. Hemiculanus plumosvs, Claiis, Die freilebeiidcii Cojjcpotleu, p. 178, pi. xxviii. fig. 12, pi. xxix. 

 figs. 1-7. 



Habitat. Station 2, 50 fathoms (night coUcetion). Lat. 6° 38' N., long. 12° 37' W., 25 

 fathoms (day collection). Lat. 3° 55' 3" N., long. 4' 7' 3" E., 30 fathoms (day collection). 

 Lat. 1° 55' 5" N., long. 5° 55' 5" E., 360 fathoms (day collection). Station 23, 85 fathoms 

 and 235 fathoms (day collections). 



This appears to bea sciirce species in the ' Buccaneer collections ; only a few specimens 

 have been ol)tained. Claus {Joe. cit.) gives a very full description and some very good 

 figures of this Hemicalanits. Hemicalamts jj^mnosua comes very near Hemicalamis 

 orientalis, Brady, described in the ' Report on the ' Challenger ' Copepoda.' 



Hemicalanus mucronatus, Claus. 



1863. Hemicalanus mucronatus, Claus, loc. cit. p. 179, pi. xxix. fig. 2. 



Length (exclusive of the tail-setse) of the specimen figured 3'8 mm. (the length varies 



in diiferent specimens). Body somewhat cylindrical. Head pyramidal, the apex mucro- 



nate^in some specimens spiniform, the postcro-Iateral angles of last thoracic segment 



rounded. Anterior antennse, reaching to beyond the caudal stylets, 25-jointed. The 



proportional lengths of the joints are represented very nearly by the annexed formula : — 



40 . 10 . 15 . 17 ■ 18 ■ 18 ■ 18 . IS ■ 21 . 20 . 22 . 23 . 30 . 34 . 34 . 35 . 37 . 37 . 33 . 28 . 30 . 29 . 28 ■ 27 . 18 

 1 2 3 4 5 G 7 8 9 10 11 12 13 14 15 16 17 18 19 20 i!l 22 23 ^4 25" 



Posterior antenuaj similar to those of H. 'plumoms. The mouth-organs are also similar 

 to those of that species, except that the anterior foot-jaws are weaker, the spines on the 

 second and third joints of the same foot-jaws are shorter and more slender, and the 

 terminal setse of both anterior and posterior foot-jaws are not spiniferous or ciliated as in 

 Hemicalanus flumosus. The swimming-feet are similar to those of Hemicalanus plumosus. 

 Abdomen 4-jointed, first segment much larger than the others. Caudal stylets short, 

 divergent, the terminal seta} densely p)lumose. 



Habitat. (1) Station 2, 50 fathoms toAv -netting, January 1st (night collection). (2) 

 Lat. 3° qS' N., long. 3° 42' W., 25 fathoms tow-netting, January 13th (day collection). 

 (3) Lat. 3° 22' 5" N., long. 4° 11' 8" E., 30 fathoms tow-netting, January 20th (night 

 collection). (4) Station 14, 10 fathoms tow-netting, January 21st (night collection). 

 (5) Lat, 6° 38' N., long. 12' 37' W., 25 fathoms tow-netting (day collection). (6) Lat. V 

 55' 5" E., 35 fathoms tow-netting, January 22nd (day collection). (7) Off Sao Thome 

 Island (lat. 0° 34' N., long. 6' 30' 4" E.), 20 fathoms tow-netting, January 23rd (day 

 collection). (8) Station 23, surface tow-netting, Eebruary 5th (day collection). 



Several specimens of H. mucronatus were obtained ; the size of the specimens varied to 

 some extent, and the forehead was more spiniform in some specimens than in others. This 

 species comes very near Hemicalanus aculeatus, Brady, in general form and in the 

 structure of the appendages, but is much smaller than Brady's specimen. The length 

 of the specimen described and figured in this lleport, which was one of the largest of 



SECOKD SEllIES. — ZOOLOGY, VOL. VI. 5 



