52 BRITISH COPEPODA. 



dredged in a depth of ten fathoms, on a bottom chiefly 

 of nullipores, in Mulroy Lough, Donegal. 



Section III. SIPHONOSTOMA, Thorell. 

 Fam. 9. ARTOTROGID^E, nov. fam. 



Body broad, depressed, rounded or subovate, com- 

 posed of 1012 segments, first segment very large, 

 and composed of the coalescent cephalic and first 

 thoracic somites. Anterior antenna 9 20-jointed, 

 alike, or nearly alike, in both sexes ; posterior short, 

 composed of three or four joints, sometimes bearing a 

 small 1-jointed secondary branch, and at the apex a claw 

 or a few curved setse. Mouth produced into a siphon 

 composed of the elongated labrum and labium ; man- 

 dibles stilet-shaped, simple or provided with a filiform 

 palp ; maxilla3 usually 2-branched and setiferous ; 

 first and second pairs of foot-jaws simple, prehensile, 

 clawed at the apex, 2 4-jointed. First four pairs of 

 feet 2-branched (except the fourth pair of Dyspontius), 

 each branch 3-jointed. Fifth pair small and com- 

 posed of one or two joints, or altogether wanting. 



Animals usually free, but sometimes living in the 

 cavities, or on the integument, of various marine Inver- 



tebrata. 



The British genera are Cyclopicera, Acontiophorus, 



Artotrogus, and Dyspontius. 



