6 



segregation, presumably as recent as the Pleiostocene in most 

 cases. Is there then no Eocene or Mesozoic flora, to correspond 

 with the series of snails? It is perhaps represented b}" the 

 dragon tree, Dracaena draco L., which is now extinct on Porto 

 Santo, though once common. This remarkable plant occurs 

 only in the Madeira and Canary Archipelagoes. Whether the 

 Porto Santo form differed from that of Madeira in any small 

 particulars, we shall never know. Whatever plants there 

 might be, whose isolation dated as far back as that of the snails, 

 might be expected to be woody, either trees or shrubs. One 

 such might be SideroxyJon marvndano Lowe,* a Sapotaceous 

 shrub peculiar to the Madeira Islands, and now very rare. Mr. 

 A. C. de Noronha detected it on the I. de Cima, Porto Santo, 

 but it was originally described from, various places on the Island 

 of Madeira. The remarkable thing about it is, that it belongs 

 to a tropical and subtropical group according to present day 

 distrii)ution. On looking at the geological record, however, we 

 find that in mid-tertiary times the genus existed in central 

 Europe {S. putterlicki Unger), and a related species has been 

 described by Berry from the Eocene of Tennessee. It appears, 

 howe\'er, that the really ancient flora has almost totally dis- 

 appeared, the snails ha\e sur\i\ed in abundance where the plants 

 could not. The endemic or precincti\'e plants are few and not 

 specially remarkable. I find the following recorded: 



(i.) Fiimaria laeta Lowe, an annual which is so near to F. 

 muralis that Lowe at first described it as a variety. It was 

 found on the summit of the Pico de Facho, the highest point 

 on the island, and it is possible that the seed of its ancestor was 

 con\-eved hither by birds. On the top of the same peak was 

 found a small European snail, Balea penrrsa, which ordinarily 

 inhabits trees, and is known to ha^■e very adhesive slime. It 

 seems undoubtedly to be carried from tree to tree by birds, and 

 I do not doubt that it reached Porto Santo, where it is a quite 

 isolated type, on the feet of migrating birds. The central 

 European Coccid Ortheziola vejdovskyi Sulc which I found on 

 grass roots on the Portclla Pass in Madeira, may be supposed 

 to have come in a similar manner, the young larvae clinging to a 

 bird. In J. Y. Johnson's list of Madeira birds, no less than 70 

 species are given as visitors or stragglers to the islands. 



* Misspelled in various works nicrmulana and mirmulans. 



