PREVIOUS WORK IN THE AREA 299 



Atlantic side are specifically distinct from those found on the Pacific coast. The cele- 

 brated sounding off Cape Horn forms an important link in the chain of his argument. 

 Among the five species recovered from the tallow, he found four peculiar to the Falk- 

 lands, and only one species, BiiUmiiia elegantissima, proper to the Pacific. So he records 

 his belief that " Le Cap Horn, recevant les eaux qui se divisent en suite pour aller dans 

 chaque mer, devait etre le point de depart des deux faunes dont nous venons de parler, 

 et montrer des especes appartenant aux deux series". 



D'Orbigny's theory has stood the test of time better than most of the evidence on 

 which it was based. Many of the crucial species, which he regarded as peculiar to one or 

 the other area, have since been proved to have a much wider distribution. But the fact 

 remains, and is even more fully confirmed by our own investigations, that the Falkland 

 area is faunistically distinct from the Pacific coast, and that, although it possesses species 

 of Pacific ancestry, these appear to have been derived from more distant parts of the 

 Pacific than the immediately adjacent coast of South America — " round the corner", so 

 to speak. 



Many of d'Orbigny's species have no great specific value. They are, at best, the 

 local forms of other well-known and older species. But we have, in this report, for the 

 most part accepted them for reasons of history and sentiment, while pointing out their 

 affinities to better known forms. 



An attempt was made to verify the determination of our specimens of the d'Orbigny 

 species recorded in this report, by comparing them with his original Type specimens. 

 With this object in view, one of us (E. H.-A.) spent a considerable time in Paris, where, 

 by the courtesy of Prof. Marcellin Boule, he examined and compared such Types as are 

 available in the Laboratoire de Paleontologie attached to the Musee d'Histoire Naturelle. 

 Unfortunately, during the century which has elapsed since d'Orbigny deposited his 

 Types in the Museum, vicissitudes which have considerably obscured the enquiry have 

 occurred, not the least of which was the flooding of the whole of the lower floors of the 

 Museum in the great rising of the Seine in the year 1910. 



It is impossible, after this lapse of time, to say in what condition and in what form 

 d'Orbigny left his specimens, and those preserved in the Musee Fleuriau de Bellevue at 

 La Rochelle, which Heron- Allen also examined, do not throw light on the subject, so 

 far as the Amerique Meridionale specimens are concerned. D'Orbigny, so far as we 

 know, from observations at La Rochelle, mounted his specimens on oblong slips of 

 brown paper, or enclosed them, when numerous, in small glass-topped boxes.^ 



The Paris "Types " consist of selected specimens attached with copious gum-arabic 

 (which is very hygroscopic) to slips of glass measuring 5^x1 cm. Under this glass slip 

 a piece of blue paper is inserted, which throws up the specimen, and the whole is en- 

 closed in a small glass tube, which in turn is fastened with a heavy smear of cement to a 

 board 8 cm. long, but of varying breadth, which board bears in manuscript the name and 

 sometimes the locality of the enclosed specimens. This mounting and arrangement was, 



1 Heron-Allen, E. Alcide d'Orbigny, his Life and Work. Joum. Roy. Micro. Soc, Presidential Address, 

 1917, pp. 1-105, pis. i-xiii, and pp. 433, 434. 



