References
- 1864 . Transactions of the Royal Academy of Edinburgh ,
- Mörch . 1857 . Fortegnelse over Grönlands Blöddyr , Rink, Grönland, p. 97.
- Malacozoologische Blätter , vi 104 – 104 .
- 1865 . The Athenæum , June : 850 – 850 . [Annals for September, p. 197.]
- 1854 . Researches upon Nemertians and Planarians Philadelphia
- Lectures on Embryology , 86 – 86 . 8vo.
- Mörch . 1863 . Contributions à la Faune malacologique des Antilles danoises . Journ. de Conch. , : 19 – 19 .
- Vergleichende Anatomie , 329 – 329 .
- 1839 . Exercices zootomiques , : 54 – 54 . t. 3. f. 4–6 (Mém. de l'Acad. Roy. des Sciences de Bruxelles, tome xi.)
- Ann. Nat. Hist. ser. 2 , i 208 – 208 . pl. 20. .f 2. Quite different from “the prehensile collar” of the same authors in their ‘British Nudibranchiata.’
- Quatrefages . 1844 . Mémoire sur les Gastéropodes phlébentérés . Ann. Sc. Nat. 3 sér. , i : 155 – 155 . t. 4. f. 4); Mörch, “Contributions à la Faune malacologique des Antilles danoises,” l. c. p. 24.
- Archiv für Naturgeschichte , xxiv 2692 – 2692 . t. 11. f. 5.
- According to Williamson closely allied to the Annelida British Association Report 1857