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THE ESSEX NATURALIST
Phylum CHORDATA
Sub-Phylum TUNICATA
Class ASCIDIACEA
Order Enterogona
DIDEMNIDAE
Didemnum maculosum (Milne Edwards)
Dredged in Thirslet Creek, 13.9.1960. Probably common.
CIONIDAE
Ciona intestinalis (Linne)
Common, often in large clusters, on the shelly bottoms of
creeks, on oyster beds and as fouling on posts and anchored ships.
Perophoridae
Perophora listeri Forbes
Dredged in Thirslet Creek (14.7.1960) and off St. Peter's Plats
(19.7.1960). Mostly growing on hydroids. Probably common.
Ascidiidae
Ascidiella aspersa (O. F. Muller)
Very common on oyster grounds where there is a mixture of
shell and mud. Often attached to the insides of empty Crepidula
shells. The commensal Copepods Ascidicola rosea and Notodelphys
allmani are often found in the pharynx of this animal.
Ascidia mentula O. F. Muller
Mostly found on clean shelly ground; the individuals being in
small clusters attached to old shells.
Ascidia conchilega O. F. Muller
Mostly found on clean shelly ground. May be common, but
in the routine bottom fauna sampling few specific identifications
within the genus Ascidia were made.
Order Pleurogona
Styelidae
Dendrodoa grossularia (van Beneden)
Abundant on clean shelly and stony bottoms, particularly on
stations TL.2 and TL.3 where counts of over 8,000 animals per
m3 have been made. Distributed from about the Thirslet area to
offshore waters.
Botryllus schlosseri (Pallas)
Common on hydroids and weeds in Thirslet Creek.
Botrylloides leachi (Savigny)
Common on hydroids and weeds in Thirslet Creek.