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LIST OF BRITISH NUDIBRANCHIATE MOLLUSCA. 



By Tom Ieedale and Chas. H. O'Donoghue, D.Sc. 



Bead 8th December, 1922. 



Some years ago one of us (Iredale) checked the names given in the 

 Conchological Society's List of British Marine MoUusca, 2nd edition, 

 published in 1902, in accordance with the International Rules 

 governing nomenclatural usage, obtaining some curious results. 

 It was considered inopportune to publish the corrections as a whole 

 owing to the complex nature of some of the problems, but some notes 

 were recorded in the Proceedings of this Society at various times, and 

 in Vol. XIII, 1918, pp. 29-30, the cases of the Nudibranch names 

 Tritonia and Doto were discussed. The other collaborator 

 (O'Donoghue) has been working for some years on the Nudibranchs 

 of North-west America, and visiting England the opportunity has 

 been taken of revising the nomenclature and grouping of the British 

 forms, as necessary for the stabilization of a world study of the group. 



With this apology we may pass to the history of the study of these 

 interesting molluscs. 



In his tenth edition of the Systema Naturae, Linne introduced a 

 genus Doris for a single , species of Nudibranch mollusc, which he 

 called Doris verrucosa. This was based on a specimen described 

 by Rumph and figured in Seba, and is at present indeterminable, 

 though Morch has suggested it may be a Phyllidia ! 



In the twelfth edition Linne added three other species, hilamellatus, 

 IcBvis, and argo. Doris hilamellatus he referred to Limax hilamellatus, 

 of the Fauna Suecica 2094, 1761, which is apparently a planarian, 

 but the description here given is amplified from a nudibranch. 

 D. Icevis is now the type of Cadlina, and D. argo was based on 

 Bohadsch's genus Argus, which Bohadsch did not specifically name, 

 but was well described and was later generically named Platydoris 

 by Bergh, on the contention that Argus, Bohadsch, was not 

 available. Under the present rules Argus must be accepted. 



0. F. Miiller, in his Zoologica Danica Prodromus published in 

 1776, described in short diagnostic sentences no fewer than twelve 

 species. Some of these were figured in the next few years in his great 

 work, the Zoologica Danica, but owing to his death some were left 

 unfigured by the editors of the continuation of the work. 



Gmelin incorporated in his Systema Naturae, under binomial 

 names, many other species described by non-binomial authors, but, 

 of course, included all in Doris as Miiller had done, and made no 

 addition whatever to our knowledge of the group. 



Cuvier then dissected and differentiated several groups, and this 

 marks the beginning of the segregation of the molluscs without shells, 

 but one of the greatest natural history works was later prepared by 

 two Englishmen, Alder and Hancock. Montagu and Fleming had 



