CLASSIFICATION OF THE 'TTEROPODA' 



In the phylum Mollusca there are still always some groups, the systematic place of 

 which has usually been misunderstood. Partly this must be attributed to the still very incomplete 

 knowledge we possess about their anatomy and embryology, so that many and serious 

 investigations are still necessary to throw some light on affinities, difficultly to be discovered — 

 partly, however, also to conservative ideas, a habit to keep old divisions and notions — I 

 should nearly saj- : though the zoologists themselves knew better. 



But this being the case, the more it is every investigator's duty, who has had the 

 opportunity to study such a "doubtful" group, to point out wherever he can, the phylogenetic 

 affinity of the group to others. For this relation, though it has been proved long ago, has not yet 

 generally been accepted. So it will perhaps not be bad to give once more a short survey of the 

 different opinions, which have prevailed and prevail still with respect to the systematic position. 



We need not stop long at the opinions of the first investigators, who wished to classify 

 the Pteropoda with other groups. So in 1756 Browne ^) classified some animals which he 

 described as Clio among the Zoophytes; while ForskAl ^) thought that .his "■ Anomia tridentata' 

 belonged to the group of the Acephala. 



Lamarck ^) was of the same opinion afterwards ; he too brought Clio and Pneumo- 

 noderiiia to this class, and thought that they formeel a transition of the Acephala to the 

 Gastropoda. On the expedition of Lapeyrouse Lamartinière *) found an animal which he 

 recognised as having been described by Browne, and classified it among the Insects. In those 

 years the lower animals were all grouped with the Insecta or the Vermes. Pallas '), who 

 examined ^ Clione dorealis'\ found some resemblance with the genus Sepia of Linnë. 



With Cuvier's examination of '^ Clio borealis\ the systematic place of this animal became 

 somewhat more distinct. Cuvier •*) denied the affinity with his Cephalopoda and found the 



1) The civil and natural histoiy of Jamaica, p. 3S6. 



2) Faune arabique. p. 124, 1773. 



3) Philosophie Zoölogique. Vol. I, p. 319. 



4) Journal de physique. Septembre 1787. 



5) Spicilegia zoologica. Fase. X, p. 28, tab. I, fig. N" 19, 1774. 



6) Mémoire sur Ie Clio borealis. Ann. Mus. d"Hist. Nat. Paris 1802, Vol. II, p. 249. 



