Ill PODOPLEA—ISOKERANDRIA Ff 3 
Echinoderms, Annelids, Molluscs, and Tunicates. Lichomolgus 
agilis (Fig. 38) occurs in the North Sea, Atlantic, and Mediter- 
ranean, on the gills of large species of 
the Nudibranch, Doris, while LZ. albeus 
is found in the peribranchial cavity and 
cloaca of various Ascidians.  Sabel- 
liphilus may infect the gills of Annelids 
such as Sabella, and is common. at 
Liverpool. 
Fam. 4. Ergasilidae. — 7hersites 
(Fig. 39) is parasitic on the gills of 
various fishes, e.g. 7. gasterostei, which 
is common on (Gasterosteus aculeatus 
on the French and North Sea coasts, 
and may even be found on specimens 
of the fish that have run up the River 
Forth into fresh water. The animal Fic. 38. — Lichomolgus agilis, 
: *~10. Abd.1, 1st abdominal 
possesses claw-like second antennae by 
segment ; cpth, cephalothorax ; 
which it clings to its host. Th.1, 1st thoracic segment ; 
oe 2 2 Th.5, 5th thoracie appendage. 
Similarly characterised by the (After Canu.) 
Fie. 39.—Thersites gasterostet. A, 
OPE xe LOS Bs ciny 2 0 Abd. 
7 & 2, Fused 1st and 2nd ab- 
dominal segments; Ant.1, Ant. 2, 
Ist and 2nd antennae ; ¢.s, egg- 
sac; Zh, thoracic appendages. 
(After Gerstaecker. ) 
absence of a siphon are three other families of fish-parasites, the 
Bomolochidae, Chondracanthidae, and Philichthyidae. 
Fam. 5. Bomolochidae.—omolochus (Fig. 40), parasitic on 
the skin of the Sole (So/ea) and in the nostrils of Cod (Gadus), 
is held to be related to the Ergasilidae. The first thoracic limb 
is remarkably modified. Were it not for the absence of a siphon, 
it would be hard to separate this family from the Caligidae. 
