348 



Introduction to Animal Morphology. 



pyrifbrm Ergasilus lives on the gills of eels, Lichomolgus in 

 Ascidians. 2. Argulinidae body flattened ; cephalothorax 

 and abdomen fused ; post-abdomen small ; eyes two, aggre- 

 gate ; two pair of maxillipedes ; females with no egg-sacs ; 

 front antennae hook-like, the second jointed ; abdominal feet 

 only cleft at the tip; liver multiramose ; proboscis protrusible, 

 with two annular poison glands ; front maxillipedes forming 

 sin kers (Argulus) or hooks (Gyropeltis). 3. Caligidx flat; 

 cephalothorax discoidal ; post-abdomen small, often un- 

 jointed, with two terminal lamellae. The front pair of an- 

 tenna; are fused at base, and only the last two (Caligus, 

 Dinemura, Pandarus) or three (Laemargus, Elytrophora) ; 

 joints free; the mandibles are two stilets within the suctorial 

 proboscis ; the females carry egg-sacs. 4. Dichelestidoe 

 cephalothorax small, separate from the five abdominal 

 somites ; anterior antenna: free, many-jointed ; second hook- 

 like ; males unknown; first pair (Dichclestium), or all the 

 abdominal feet, two-branched (Kroyeria). 5. Chondracan- 

 tlmku worm-like, with small cephalothorax, a rudimental 

 pair of foot-jaws; abdominal feet leaf-like; males pigmy; 

 abdomen unse^inented 



(Chondiacanthus), or F - 4 



the three foremost joints 

 united, the fourth nar- 

 row, and the fifth very 

 long (Peniculus). 6. 

 Lerruvopoda worm- 

 like, with a pairof pigmy 

 males on each female ; 

 body formed of two 

 segments (cephalotho- 

 rax and abdomen) ; the 

 second pair of maxilli- 

 pedes unite in a terminal sucker; cephalothorax pyriform 

 (Achtheres), or worm-like (Anchorella, Tracheliastes). 7. Pen- 

 nellidce worm-like, with a short, unjointed cephalothorax 

 with unjointed limbs, lateral suckers, and minute abdominal 

 feet. Pennella has a feather-like post-abdominal appendage 

 (Fig. 40). 



A, Pennella Orthagorisci. B, head magnified. 



