30
THE ESSEX NATURALIST
bottom fauna subsequently. Usually found among sponges and
hydroids.
Gnathiidae
Gnathia maxilliaris (Montagu)
The praniza larvae were taken in plankton samples in 1960.
Also recorded from the bottom fauna on the Bradwell shore.
Limnoriidae
Limnoria lignorum (Rathke)
Commonly found boring into old wood on the middle and lower
shore and below low water mark. Recorded from all shores of
the Blackwater seawards of Osea Island.
Sphaeromatidae
Sphaeroma monodi Bocquet
Specimens collected from the benthos at Thirslet and seawards
are normally identified as this species. Also common on the lower
shore.
Sphaeroma rugicauda Leach
Some specimens were collected from the Blackwater at Maldon
in 1963. Probably common in brackish waters.
Idoteidae
Idotea balthica (Pallas)
Recorded on two occasions; 3.9.1959 and 25.4.1960, in fouling
on ships anchored in the Blackwater.
Idotea pelagica Leach
Two specimens only, in dredge sample taken at the Knoll
Buoy, 25.5.1962.
Idotea linearis (Linne)
Common in the plankton and on floating wood and detritus,
especially in summer.
Janiridae
Janira maculosa Leach
Common in dredge and grab samples from clean shelly or stony
bottoms, especially where there are sponges and hydroids growing.
Generally distributed from Thirslet to the Bar Buoy and seawards.
Jaera albifrons Leach
Very common on the middle and lower shores, particularly
where there is some inflow of freshwater. Usually under stones
and shells.
Ligiidae
Ligia oceanica (L.)
Common along high water mark on sea walls and amongst
litter at the top of the shore. Recorded from Maldon seawards.