CALIGIDiE. 
257 
flat, and two-jointed. Second pair of foot-jaws of two 
articulations, and not in form of a sucking disc. Thoracic 
segments uncovered. 
Bibliographical History. — Linnaeus seems to be the 
first author who takes notice of any animal belonging to 
the genus Caligus. In his £ Fauna Suecica/ second edition, 
1761, he shortly describes a species which lives upon the 
salmon and haddock, inhabiting the Norwegian seas. He 
designates it “Monoculus piscinus” and quotes Martin as 
his authority for the habitat. In the same work he de- 
scribes a species of Pediculus, which is found upon the 
salmon also, calling it the “ Pediculus FarionisP From 
the general description of this little creature, and more 
especially from its possessing two long ovarian tubes, it is 
evident that it is a species of Caligus, and from its being 
found upon the same species of fish, it would appear to be 
closely allied to the Mono cuius piscinus. In his £ System a 
Naturae/ 12th edition, 1767, he, indeed, distinctly affirms 
this, and says it is ££ allied to the Monoculus piscinus from 
its having two cylindrical bodies placed above the tail / ’ 
and Gmelin, in his edition of 1788, under the species 
“ Pediculus Farionis,” remarks, “ that it scarcely belongs 
to this genus.” Strom, in his £ Physiske og Oeconomisk 
Beskrivelse over Fogderiet Sondmor/ 1762, describes and 
figures what may be two species of Caligus, but which are 
perhaps only the male and female, under the name of 
Fiske luus , or Pediculi mar ini ; and Baster, in his 
£ Opuscula Subseciva/ 1765, describes and figures also 
two or three different species of this genus, accompanied 
with considerable details. Both of these authors repre- 
sent the animal with its head downwards, and considered 
the two long ovarian tubes as antennae, mistaking the tail 
for the head. These figures and descriptions appear to 
have misled Linnaeus ; for, notwithstanding his having 
already described the animal correctly in his £ Fauna 
Suecica/ he subsequently, in the 12th edition of his 
£ Systema Naturae/ 1767, describes the Monoculus piscinus 
17 
