Amaroucium ficus Alder & Hancock, 1912 accepted as Synoicum pulmonaria (Ellis & Solander, 1786) (original description)
Amaroucium papillosum Alder & Hancock, 1912 accepted as Aplidium proliferum (Milne Edwards, 1841) (original description)
Aplidium melleum Alder & Hancock, 1912 accepted as Aplidium pallidum (Verrill, 1871) (original description)
Ascidia alderi Alder & Hancock, 1912 accepted as Ascidia mentula Müller, 1776 (original description)
Ascidia amoena Alder & Hancock, 1912 accepted as Ascidia conchilega Müller, 1776 (original description)
Ascidia crassa Alder & Hancock, 1912 accepted as Ascidia mentula Müller, 1776 (original description)
Ascidia depressa Alder & Hancock, 1912 accepted as Ascidia conchilega Müller, 1776 (original description)
Ascidia elongata Alder & Hancock, 1912 accepted as Ascidia conchilega Müller, 1776 (original description)
Ascidia inonata Alder & Hancock, 1912 accepted as Ascidia conchilega Müller, 1776 (original description)
Ascidia morei Alder & Hancock, 1912 accepted as Ascidiella scabra (Müller, 1776) (original description)
Ascidia plana Alder & Hancock, 1912 accepted as Ascidia mentula Müller, 1776 (original description)
Ascidia plebeia Alder & Hancock, 1912 accepted as Ascidia conchilega Müller, 1776 (original description)
Ascidia producta Alder & Hancock, 1912 accepted as Ascidia conchilega Müller, 1776 (original description)
Ascidia robusta Alder & Hancock, 1912 accepted as Ascidia mentula Müller, 1776 (original description)
Ascidia rubicunda Alder & Hancock, 1912 accepted as Ascidia mentula Müller, 1776 (original description)
Ascidia rubrotincta Alder & Hancock, 1912 accepted as Ascidia mentula Müller, 1776 (original description)
Ascidia rudis Alder & Hancock, 1912 accepted as Ascidia mentula Müller, 1776 (original description)
Botrylloides vinosa Alder & Hancock, 1912 accepted as Botrylloides leachii (Savigny, 1816) (original description)
Botryllus badius Alder & Hancock, 1912 accepted as Botryllus schlosseri (Pallas, 1766) (original description)
Botryllus calyculatus Alder & Hancock, 1907 accepted as Botryllus schlosseri (Pallas, 1766) (original description)
Botryllus miniatus Alder & Hancock, 1912 accepted as Botryllus schlosseri (Pallas, 1766) (original description)
Cynthia ovata Alder & Hancock, 1907 accepted as Pyura squamulosa (Alder, 1863) (original description)
Molgula valvata Alder & Hancock, 1907 accepted as Eugyra arenosa (Alder & Hancock, 1848) (original description)
Parascidia flemingi Alder & Hancock, 1912 accepted as Aplidium turbinatum (Savigny, 1816) (original description)
Parascidia forbesi Alder, 1863 accepted as Aplidium turbinatum (Savigny, 1816) (additional source)
Polyclinum cerebriforme Alder & Hancock, 1912 accepted as Polyclinum aurantium Milne Edwards, 1841 (original description)
Polyclinum succineum Alder & Hancock, 1912 accepted as Aplidium turbinatum (Savigny, 1816) (original description)
Styela apalina Alder & Hancock, 1907 accepted as Polycarpa pomaria (Savigny, 1816) (original description)
Styela depressa Alder & Hancock, 1907 accepted as Polycarpa tenera Lacaze-Duthiers & Delage, 1892 (original description)
Styela fibrillata Alder & Hancock, 1907 accepted as Polycarpa comata (Alder, 1863) (original description)
Styela obscura Alder & Hancock, 1907 accepted as Polycarpa tenera Lacaze-Duthiers & Delage, 1892 (original description)
Styelopsis sphaerica Alder & Hancock, 1907 accepted as Dendrodoa grossularia (Van Beneden, 1846) (original description)
Thylacium Alder & Hancock, 1907 accepted as Stolonica Lacaze-Duthiers & Délage, 1892 (original description)
Thylacium aggregatum Alder & Hancock, 1907 accepted as Stolonica socialis Hartmeyer, 1903 (original description)