| Archaphanostoma agile (Jensen, 1878) | Apr, May 1963 | | detritis-rich shell-sand mix | |
| Coelogynopora bresslaui Steinböck, 1924 | summer 1923 | | | |
| Coelogynopora biarmata Steinböck, 1924 | summer 1923 | | | |
| Convoluta convoluta (Abildgaard, 1806) | 1963-1964 | | dulse algae | |
| Pseudoposthia macrogonopora Westblad, 1946 | Apr, May 1963 | 5 m | shell sand mixture, fine sand | |
| Pseudoposthia macrogonopora Westblad, 1946 | Apr, May 1963 | 40 m | detritus rich sand | |
| Pseudoposthia macrogonopora Westblad, 1946 | Apr, May 1963 | 42 m | mud, sand | |
| Pseudoposthia macrogonopora Westblad, 1946 | Apr, May 1963 | | rock, gravel | |
| Archaphanostoma histobursalium Dörjes, 1968 | Aug 1963 | deep gully | mud | |
| Postaphanostoma atriomagnum Dörjes, 1968 | Apr 1963; Jul 1964 | 18 m | Amphioxus sand, coarse sand | museum specimen number: SMF 3019-36 / Amphioxus |
| Postaphanostoma filum Dörjes, 1968 | Apr 1963 | 18 m | Amphioxus sand, coarse sand | museum specimen numbers: SMF 3037-59; SMF 3463-65 / Amphioxus |
| Postaphanostoma filum Dörjes, 1968 | Aug 1963 | 17-18 m | coarse sand, Amphioxus sand | |
| Childia trianguliferum (Westblad, 1942) | Aug 1963 | 17-18 m | coarse sand, Amphioxus sand | |
| Proxenetes cochlear uncinatus Graff, 1882 | prior to 1882 | | | sea water aquarium. water likely from Helgoland. |
| Monotus fusca (Ørsted, 1843) | prior to 1882 | | | |
| Convoluta paradoxa Ørsted, 1843 | 1882 or earlier | | | |
| Convoluta paradoxa Ørsted, 1843 | 1847 or earlier | | | |
| Nemertoderma sp. Westblad, 1937 | | | mud coarse sand | station 12a, Dune, Helgoland. |
| Microstomum album (Attems, 1897) | 1913 or earlier | | | slow moving bertween plants and hydroids on beaches of Denmark, Helgoland and ? [Graff questions] Banyuls-sur-mer. |
| Alaurina composita Metschnikoff, 1861 | 1913 or earlier | | | North Sea including Helgoland and Danish waters. |
| Proxenetes flabellifer Jensen, 1878 | 1913 or earlier | | | beach water. |
| Promesostoma marmoratum (Schultze, 1851) | 1913 or earlier | | | very active, in marine and brackish water. |
| Promesostoma marmoratum marmoratum (Schultze, 1851) | 1913 or earlier | | | very active, in marine and brackish water. |
| Promesostoma marmoratum nudum Graff, 1905 | 1913 or earlier | | | |
| Plagiostomum vittatum (Frey & Leuckart, 1847) | 1913 or earlier | | | |
| Plagiostomum vittatum (Frey & Leuckart, 1847) | 1896 or earlier | | | |
| Vorticeros auriculatum (Müller, 1784) | 1913 or earlier | 0-35m | | littoral up to 35 m deep in Algen and Bryozoen. |
| Pseudostomum quadrioculatum (Leuckart, 1847) | 1913 or earlier | | | |
| Pseudostomum klostermanni (Graff, 1874) | 1913 or earlier | | | |
| Monocelis fusca Örsted, 1843 | 1913 or earlier | | | |
| Monocelis lineata (Müller, 1773) | 1913 or earlier | | | |
| Monocelis longiceps (Duges, 1830) | 1913 or earlier | | | |
| Orthoplana borealis (Steinböck, 1931) | 1932 or earlier | | | |
| Mariplanella frisia Ax & Heller, 1970 | May 1970 | | coarse sand | Amphioxus-Grund. 2 specimens. |
| Gyratricella attemsi (Graff, 1913) | prior to 1938 | | | Bisher nur aus der Litoralzone der Küste von Helgoland. |
| Leptoplana sp. Apstein, 1892 | 1892 or earlier | | | Helgoland, North Sea. |
| Coelogynopora gynocotyla Steinböck, 1924 | summer 1923 | | | Helgoland. |
| Allostoma pallidum Beneden, 1861 | 1933 or earlier | | | |