OBSERVATIONS ON THE ARGULUS FOLIACEUS, (Jurine), 
AS INJURIOUS TO GOLD AND SILVER FISHES. 
Genus 85. Argulus, Mull,, Jurine, Leach, Desmarest, Samouelle: 
Binoculus, Geojfroy, Latreille. 
/SMZ oval, somewhat membranaceous, semi-transparent, anteriorly rounded, 
deeply notched behind: two hemispheric eyes inserted at the anterior and lateral 
parts of the clypeus: antennae very small, inserted above the eyes: rostellum 
sterniform: twelve legs, unequal in size and form; first pair shorter, very mem¬ 
branaceous, capable of changing their form, broader at their tips, and constructed 
for adhering to objects; second pair prehensile, curved, much thicker towards 
their base, the thighs furnished with three spinules beneath; tarsi of the second 
pair three-jointed, the last joint with two claws and a pul villus ; four hinder pairs 
inserted at the sides of the abdomen, somewhat cylindric, formed for swimming, 
with their points bifid: abdomen cylindric ; tail bilobate. 
Sp. 1. Arg. foliaceus , Jurine. 
Argulus delphinus , Miill., Linton., 123. Monoculus Argulus, Fabr., Ent. 
Syst ., 489. Argulus foliaceus, Leach, Suppl. to Encycl. Brit., p. 405. 
Desmarest, Considerations des Crust., p. 329, pi. 50, fig. 1 , a. e. 
