110 



Part III. — Twenty -third Annual Report 



Genus Pseudocaligus, A. Scott (1901). 



Pseudocaligus brevipedis (Bassett-Smith). 



1896. Ccdigus brevipedis, Bassett-Smith, Ann. and Mag. Nat. 



Hist. (6), vol. xviii., p. 11, pi. iii., fig. 1. 

 1901. Pseudocaligus brevipedis, A. Scott, Trans. Liverpool Biol. 



Soc, vol. xv., p. 350, pi. ii., figs. 1-4. 



Habitat. — Found attached to the base of the tongue of a Three-bearded 

 Rockling, Onos tricirratus, captured at the mouth of the River Dee, 

 Aberdeen, November 23, 1904. Eight specimens of a Bomolochus, 

 probably B. onosi, were also found on the same fish adhering to the gills 

 and gill-arches. 



Genus Lepeophtheirus, Nordmann (1832). 



Lepeophtheirus sturionis, Kroyer. PI. v., figs. 7-14. 



1837. Lepeophtheirus sturionis, Kr., Tidsskrift, i., Tab. vi., fig. 6. 



Description of the female. — The female of this species has a general 

 resemblance to that of Caligus diaphanus, Nordmann, but is much larger, 

 being fully half an inch in length (about 14mm.). 



The cephalic shield is nearly circular in outline, and the frontal plate, 

 which is not very prominent, is without lunulas. 



The last thoracic segment is considerably shorter than the cephalic 

 shield, and is only slightly longer than broad. 



Abdomen moderately narrow and elongated, being equal to nearly 

 three-fourths the length of the last thoracic segment. Furcal joints very 

 short (fig. 7). 



The basal joints of the antennules are considerably dilated, and the 

 end joints though short are also tolerably stout (fig. 8). 



Antennas robust and armed with a large and strong claw, the distal end 

 of which is bent at nearly a right angle, as shown in the drawing (fig. 9). 



The mandibles resemble those of L. pectoralis, O. F. Muller. 



The basal-joint of the second maxillipeds is moderately stout and 

 elongate, and armed with a short but strong terminal claw (fig. 11). 



The " palpi," though slightly dilated at the base, have the sides nearly 

 parallel, and the two branches of the bifid extremity are tolerably 

 elongated (fig. 10); the small appendage at the bases of the palpi bear 

 each one moderately large spine and two small ones, as shown in the 

 drawing. 



Sternal fork very stout and with triangularly divergent branches 

 (fig. 12).* 



Fourth pair of thoracic legs stout, each with a single three-jointed branch ; 

 the outer distal angle of the first joint in each branch terminates in a 

 small tooth, a stout spine springs from the outer distal angle of the 

 second joint, while the end joint is armed with three terminal spines of 

 varying lengths (fig. 13). 



The short furcal joints bear a few small apical setse or spines (fig. 1'4). 



Habitat. — Taken from a Sturgeon, Acipenser sturio, Linn., captured 

 about 1 6 miles S.E. by E. of Aberdeen, and landed at the Fish Market, 

 Aberdeen, on December 29, 1904. I am indebted to Mr. Bowman, 

 Aberdeen, for thh- addition to the marine copepod fauna of Scotland. 



* Kroyer in Naturh. Tidsskr. 1 Band (1837), PI. vi., fig. 66, shows the ends of the 

 branches of the sternal fork slightly bifid ; but the figure in Naturh. Tidsskr. 3 R., 

 2 B. (1863), PI. xvii., fig. 4, represents the sternal fork of another form bluntly pointed 

 at the ends, and with which our figure is identical. 



