PREFACE. xvii 



collection were obtained from Socotra during the period of its occupation 

 by Indian troops (1834-39). Whenever a plant of this collection is identical 

 with a Socotran one known from no other locality, I have had no hesitation 

 in assuming that the specimen was brought from Socotra; in this way several 

 species are taken out of the tropical African flora. 



A few plants have the name ' Boivin ' attached. Louis Hyacinthe Boivin 

 was botanist on board the ' Duconadec,' under Captain Guillain, during the 

 exploration of the east coast of Africa (1846-52), and in 1847 the ship was at 

 Socotra for a few days, and Boivin obtained some plants. I have only seen three 

 plants of his collecting, but one of them, Lagarosiphon Roxburghii, has been 

 brought from Socotra by no other collector. Possibly in the herbarium at 

 Paris there may be more specimens of Boivin's collection. 



Some of the species have the name ' Hunter ' attached. These are species 

 which occur in a small collection made by Captain (now Major) Hunter, 

 Assistant Political Resident at Aden, who visited the island in his official 

 capacity in 1876, and presented to the herbarium of the Royal Botanic Garden, 

 Edinburgh, in 1878, by Dr George Hay, Port-Surgeon at Aden. 



' Perry ' is attached to some species, and refers to plants brought by Com- 

 mander Wykeham Perry from Socotra in 1876 ; the chief one being the aloe 

 which is named after him. 



' Collins ' refers to Mr James Collins, who was Curator of the Museum 

 of the Pharmaceutical Society, and went out many years ago, as Mr Baker 

 informs me, to Singapore to superintend india-rubber plantations. On his 

 way home he obtained the Socotran aloe. 



In the introductory chapter, which is in its greater part the address 

 I delivered to the Society, at the invitation of the Council, on 4th July 1881, 

 I have briefly summarised what we know of the history, people, geology, and 

 zoology of the island, giving references to literature where further infor- 

 mation may be obtained. Upon the botanical features of the island I have 

 dwelt at greater length. But after all that is said what we know is but a small 

 portion of what there is to know. Besides the many interesting points in the 

 botanical, zoological, and geological features that still await investigation, there 

 is the fascinating problem of race and language yet to solve. Our expedition 

 was, as I have elsewhere said, merely a raid, during which as much informa- 

 tion and as large collections as possible were accumulated. My want of know- 

 ledge of Arabic and kindred tongues made it difficult for me in the time, and 

 with the means at my disposal, to make satisfactory inquiries into questions 

 which might conduce to the clearing up of the mystery that at present surrounds 

 the origin of the people and their speech. In the case of the German expedi- 

 tion, which was fortunate in being accompanied by so competent an explorer 

 as Dr Schweinfurth, the sojourn on the island was so short that researches 



TRANS. ROY. SOC. EDIN, VOL. XXXI. C 



