INTRODUCTORY CHAPTER. xxxiii 



Prof. Von Martens,* who worked out the land-mollusca collected by the 

 German Expedition, questions the identifications upon which Godwin- Austen 

 bases his view of the connection of Socotra with Madagascar. Upon this 

 Godwin- Austen remarks (I.e., p. 3) : — " Herr Von Martens, the recorder of 

 the molluscan portion of the Zoological Record for 1881, does not quite agree 

 with me in connecting Socotra with Madagascar, considering the species I 

 placed in Tropidophora to belong rather to Lithidion. On looking again at 

 these shells, the form of the operculum of T. socotrana is certainly similar 

 to that of Otopoma; but that of Lithidion is nearer to Cyclotopsis and 

 Tropidophora (Arabia and Socotra)." 



In speaking of the Lepidoptera collected by us on Socotra, Mr A. G. 

 Butler t points out that the twenty-four specimens are " referable to thirteen 

 species, of which eleven are Rhopalocera ; seven of the species are new to 

 science. Of the known forms in this series one is cosmopolitan, two are found in 

 Europe, Asia, and Africa, one throughout Africa, one in south-west Africa and 

 Abyssinia, and one (with trifling differences) in south Africa. Of the new 

 forms five are allied to previously recorded types from the following localities : — 

 one from the Comoro Islands, one from south-west Africa, one from Zanzibar, 

 and two from Arabia. Without the help of these last two, it would therefore 

 be impossible for any one not acquainted with it to guess at the locality from 

 which this collection had been obtained." 



We have not a sufficiently extensive knowledge of the fauna of Socotra or 

 of that of the adjoining mainlands to enable us with advantage to discuss in 

 detail the affinities. It is probable that there is a considerable endemic 

 element, and what we do know indicates in some groups strong north-east African 

 connections, in others relations with the faunas of other islands in the Indian 

 Ocean ; whilst in other groups a preponderance of Arabian and south- 

 west Asiatic forms is visible, as well as a distinct strain of Indian and 

 Eastern resemblances. 



Vegetation and Flora. 



The vegetation of Socotra varies greatly in aspect with the character of the 

 rocks. Starting from the shore one finds no representative of a marine phanero- 

 gamic vegetation, although in the stagnant brackish waters at the mouths of the 

 streams naiads occur. The coast is not favourable for seaweeds, being too 

 shingly and sandy. 



* E. von Martens : Land Schnecken von Sokotra, in Nachrichtsbl. d. deutsch. Malekol. Gesellschaft, 

 No. 10 (1881);— Id. : Mollusken von Sokotra, Conckologische Mittheilungen, Bd. ii. pp. 140-152, 

 tt. 28-29. 



t A. G. Butler : On tlie Lepidoptera collected in Socotra, by Prof. I. B. Balfour, in Proc. Zool. 

 Soc, January 18, 1881, pp. 175-180, with plate xviii. 



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