615 



Remarlis. — This is the species first described, and may therefore be 

 regarded as the type of the genus. It has generally been recorded under 

 tlie specific name longicorne^ proposed by Fabricius, birt the name grossipes is 

 much the older, and must be retained for the species. The Cancer volutator 

 of 0. Fr. MuUer, as also Astacus linearis of Pennant, are merely synonyms. 

 The species may be readily distinguished from the other northern forms by 

 the structure of the inferior antennse in both sexes. 



Occurrence. — The only place where I have met with this form is 

 in the Christianiafjord, at Moss; but Boeck collected it also at Haugesund, 

 west coast of Norway. 



Bistrihntion. — British Isles (Sp. Bate), Bohuslan (Bruzel.), Kattegat 

 (Meinert), the Baltic (Lindstrom), Dutch coast (Hoek), coast of France (Che- 

 vreux), Adriatic (Heller). 



5. Corophium crassicorne, Bruzel. 



(ri 220). 



Corophium crasslconie, Bruzelius, t-'kand. Amph. Gauim. K. Svenska Vet. Akad. Ilaiidl. 



Ill, p. 15, PI. 1, fig, 2. 



S)'n.: Corophium spiuicorne, Sp. Bate 9- 



Body somewhat more strongly built than in the type species, and 

 having the segments of urosome completely fused together. Cephalon with 

 a distinctly defined, acute rostrum, lateral lobes very much produced and 

 acuminate at the tip. First pair of coxal plates with only 3 apical setae. 

 Eyes small, rounded, pigment dark brown with a whitish coating. Antennae 

 in female comparatively short and nearly equal in length, scarcely Vs the 

 length of the body, the superior ones with the 1st joint of the peduncle rather 

 large and expanded, about equalling in length the other 2 combined, outer 

 edge armed with a row of about 6 strong spines, inner one with 4 recurved 

 spines at the base, last joint scarcely more than Vs the length of the 2nd, 

 flagellum much shorter than the peduncle, and composed of only 6 articula- 

 tions. Inferior antennae in female rather stout, with the penultimate joint 

 of the peduncle forming inside a lamellar expansion armed with a row of 

 about 8 spines successively increasing in size distally, last peduncular joint 

 scarcely more than half as long, and having in the middle of the posterior 

 edge a strong spine ; inferior antennae in niale very strongl}' developed, though 

 scarcely attaining the length of the body, penultimate joint of the peduncle 



