348 



Introduchon to Animal Morphology. 



pyriform 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 wdth 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 

 suckers (Argulus) or hooks (Gyropeltis). 3. Caligidae — flat; 

 cephalothorax discoidal ; post-abdomen small, often un- 

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

 tennae 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. Dichelestidae — 

 cephalothorax small, separate from the five abdominal 

 somites ; anterior antennae free, many-jointed ; second hook- 

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

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

 thidae — worm-like, with small cephalothorax, a rudimental 

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

 abdomen unsegmented 



(Chondracanthus), or ^'S- 40- 



the three foremost joints 

 united, the fourth nar- 

 row, and the fifth very- 

 long (Peniculus). 6. 

 Lernasopoda — worm- 

 like, with a pair of 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- 

 nellidas — 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. 



