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Pleopoda well developed, adapted both for swimming and breathing. Uropoda of 

 a structure similar to that in the uEgidce. Incubatory pouch composed of 5 pairs 

 of lamellae issuing from the bases of the 5 anterior pairs of legs ; a supplementary 

 pair of lamellae originating moreover from the epignath of the maxillipeds. Second 

 pair of pleopoda in male with a stylet inside the inner plate. 



'Remarks. — In outward appearance, the forms belonging to this family ex- 

 hibit a great similarity to the JEgidce, and were indeed formerly referred to the 

 very same family. They are not, however, like the latter, parasitic in character, 

 but lead a free existence, and it is chiefly to this difference in habits that the 

 apparently very different structure of the oral parts, and partly also of the anterior 

 pairs of legs, is due. In other anatomical characters, the close relationship between 

 the 2 families may be easily observed. The family has been made the subject of 

 a very thorough investigation by the well-known Danish zoologist, Dr. H. J. Hansen, 

 and the reader may therefore be referred for a more detailed description to his ad- 

 mirable work, in which also the nearly-allied families, Alcinoridae, Corallanidce and 

 Barybrotidce are treated of in detail. The following 5 genera have been included 

 within the present family: Cirolana, Conilera, Bathynomus, Anuropus, and Eury- 

 dice. Of these only the first and last are represented in the fauna of Norway. 



Gen. 1. Cirolana, Leach, 1818. 



Generic Characters. — Body more or less elongated, with the dorsal face 

 strongly vaulted and perfectly smooth. Cephalon semicircular, with 1 the frontal 

 edge evenly arched. First segment of mesosome forming on each side a lingui- 

 form expansion advancing over the sides of the cephalon. Coxal plates of the 

 succeeding segments well-defined, laminar, turned downwards. Penultimate seg- 

 ment of metasome without projecting epimera; terminal segment large, more or 

 less narrowed distally, ciliated at the tip. Eyes placed widely apart on the sides 

 of the cephalon. Superior antennae very small, with the flagellum subfusiform, 

 and composed of numerous very short articulations clothed with delicate sensory 

 filaments. Inferior antennae with the flagellum slender and elongated. Epistomal 

 plate very narrow. Anterior and posterior lips normally developed. Mandibles 

 very strong, with the cutting edge divided into a limited number of coarse teeth, 

 and having, inside, a distinct denticulated secondary lamella, molar expansion nar- 

 row, ensiform, with a regular series of small denticles along the anterior edge, 

 palp not very large. Anterior maxillae with the masticatory lobe very large and 



