109 Part III. — Twenty-third Annual Report 



Fam. Caligid^e. 

 Genus Caligus, O. F. Miiller (1785). 



* Caligus abbreviatus, Kroyer. PI. v., figs. 1-6. 



1863. Caligus abbreviatus, Kr., Bidrag til Kundskab om 

 Synltekrebsene ; Naturh. Tidsskr., 2R., 2B., p. 61, pi. iii., 

 fig. 3, a-k. 



Description of the Female. — The Female represented by the drawing, 

 (fig. 1) measures 5mm. (£ of an inch). The cephalic shield is nearly 

 circular in outline, but is rather widest behind the middle; the width of 

 the frontal plate is scarcely half the width of the cephalic shield at the 

 widest part ; lunulae very clearly defined. Abdomen and f ureal joints 

 very short, as represented in the drawing. 



The antennules have the basal joints robust and broadly sub-triangular, 

 but the end joints are long and narrow (fig. 3). 



The second maxillipeds are robust, and form powerful grasping organs 

 (%• 5). 



The sternal fork, which is moderately stout, and the branches of which 

 are not greatly divergent, has a resemblance to the same appendage in 

 Lepeqphtheirus Thompsoni, Baird (fig. 4). 



The fourth pair of thoracic legs are elongated; the basal joint is 

 moderately stout and one-branched ; this branch is slender and composed 

 of two joints, and the end-joint is about twice the length of the first, and 

 is armed with a long, slender and claw-like terminal spine and a short 

 spine near the distal end of the outer margin ; the first joint is also 

 furnished with a spine on the outer distal angle (fig. 6). 



Habitat. — On a Ballan Wrass, Labrus bergylta, captured in the Moray 

 Firth in October 1904, and on another fish of the same species captured 

 in the North Sea. Kroyer also obtained his specimens of the Caligus on 

 the Ballan Wrass. 



A young specimen representing the Chalimus stage of this Caligus is 

 represented by figure 2, and was obtained along with the adult form. In 

 this specimen the siphon is still present, showing a somewhat dilated 

 and biarticalated base ; the antennules are composed of two short subequal 

 joints, the cephalic shield is elongate-ovate in outline, and the abdomen 

 is very short. The frontal plate slopes posteriorly, and the development 

 of the lunulae is considerably advanced. 



Caligus minimus, A. W. Otto. 



1828. Caligus minimus, Otto, Nova Acta Acad. Caes. Leop., 



vol. xiv., p. 354, pi. xxii., fig. 7. 

 1840. Caligus minutus, M. Edw., Hist. Nat. Crust., vol. iii., 



p. 450. 

 1901. Caligus minimus, A. Scott, Trans. Liverpool Biol. Soc, 



vol. xv., p. 349, pi. i., figs. 1-8. 



Habitat. — On a Bass, Labrax lupus, captured above Queensferry on 

 February 4, 1903. This appears to be the first record of C. minimus 

 for the Forth district. 



* This species closely resembles, and is probably identical with, Caligus cenlrodont% 

 Baird. (Of Brit. Entom., p. 272-3, Tab. xxxii., figs. 6, 7.) 

 H 



