DORIS BILAMELLATA. 



Forth; the original locality mentioned by Dr. Leach, where he states it to be very abundant. 

 M. de Blainville says that he founded his genus Onchidoris on a specimen in the British 

 Museum. It is rather remarkable that the specimen preserved in the Museum collection 

 with the name of 'Onchidoris, Blainv.' attached to it, should be an individual of D. bilamellata, 

 in which no such characters as he establishes his genus upon are to be found. Besides, he 

 figures in the * Manuel de Malaeologie' an animal with the plumes retracted within a single 

 cavity, according to his description. There is evidently a mistake somewhere with respect to 

 this genus, and until a mollusk can be found with the characters assigned to the genus 

 Onchidoris, it is desirable that it should remain in abeyance. 



Dr. Johnston was the first, we believe, to recognise in the species now under 

 consideration the Boris bilamellata of Linnaeus, and it may be necessary to say a few words 

 with respect to the propriety of adopting this view. We do not of course profess to unite 

 our species with the Limaw bilamellatus of the ' Fauna Suecica,' which appears to have been 

 an intestinal worm, but to that form of Doris bilamellata, in the 12th edition of the ' Sij sterna 

 Nature' to which the more detailed description belongs, stated, on the authority of 

 J. G. Koenig, to be " frequent on stones" in Iceland. The description, ' anus transversus, supra 

 postice corpus, ciliatus plumis simplicibus,' very well characterises our species, and Muller's 

 figure of Doris fusca in the 'Zoologia Danica,' which he makes synonymous with D. 

 bilamellata, Linn., undoubtedly represents it, though the description, as Professor Loven has 

 pointed out to us, belongs to a different species. The drawing was furnished by M. Koenig, 

 from whom Linnaeus received his specimens, and may therefore be taken as a correct 

 representation of the Linnean Doris bilamellata. 



This species appears to be widely distributed through the seas of northern Europe, 

 having been found in Greenland (Moller), Iceland (Koenig), and France (Bouchard). 

 M. Loven does not mention it in the Scandinavian Fauna, though we think it probable that 

 it will be found on the Norwegian coast. 



Fig. 1 ; 2, 3. Doris bilamellata, different views. 



4. A portion of the cloak, much enlarged, showing the tubercles. 



5, 6. Back and front views of tentacles. 



7. Enlarged view of branchial plume. 



8. Spawn. 



9. A portion of the same more highly magnified, exhibiting the ova, 

 10, Spicula. 



