CYAMUS. 'ZlM 



joints of the thorax without legs, but bearing very long 

 cylindrical respiratory appendages, which are generally bent 

 over the back. 



The species of this family are parasitic on the whale and 

 dolphin. They gnaw the rough thick skin of these marine 

 animals more or less deeply. There seem to be several 

 species of Cyamus, attacking different parts of the bodies of 

 these bulky beasts, some preferring the head and others the 

 fins and other parts of the body. 



Gen. 106. CYAMUS, Lair. 



Head small, truncated, united to first thoracic segment. 

 The characters of the genus are those of the family. 



Cyamus ceti. Whale Louse. (Plate XI. fig. 6.) — Bran- 

 chial appendages simple, and furnished at the base with two 

 unequal and pointed appendages. 



Under the fins, etc., of the whale. 



Cyamus ovalis. — Body much wider than in last; four 

 pairs of branchial appendages in both sexes, those of third 

 ring with a single short slender appendage at the base, those 

 of the fourth ring with two of unequal length. 



Lives in clusters on the hard projections of head of whale. 



The Cyamus gracilis and Cyamus Thompsoni are also re- 



