464 ANIMALS INTRODUCED UNAWARES 



former of which has been captured in British hothouses, 

 have become naturalized in the greenhouses of Central 

 Europe and have multiplied so greatly as to become pests. 



Several other classes of animals have their foreign 

 representatives in our hothouses. An exotic Myriopod, 

 Paradesmus gracitis, is well established in several such 

 retreats about Edinburgh, individuals of all ages having 

 been noticed by Mr W. Evans. Even Worms have thus 

 been added to our fauna : a wiry, agile, Indian species of 

 Earthworm, Perichaeta indica, which like its congeners 

 possesses unusual activity and power of springing when 

 touched, occasionally accompanies plants, and has become 

 naturalized in the congenial climate of hothouses in Kirk- 

 cudbrightshire and Edinburgh. Perichaeta is familiar to 

 gardeners in this country, and though its home is in the East, 

 the genus is now widely distributed in Europe and America 

 evidence of the ease with which its members, hidden in soil 

 about plant roots, can be transported by man. 



It would, however, be matter for surprise that "Leaf- 

 worms " or Land Planarians, which, like Placocephalus (Bi- 

 palium) kewensis, may measure 6 to 9 inches in length, and 

 sometimes attain 18 inches at full stretch, should have 

 been introduced unobserved, were it not that they too, like 

 Earthworms, burrow in the soil under conditions of drought. 

 Clearly the species just mentioned is no rare wanderer from 

 its home in the tropics, for it has been observed in several 

 Scottish greenhouses, and has been imported with tropical 

 vegetation and soil to England, Germany, South Africa, 

 and Australia. The transference to foreign and unaccustomed 

 climes has had one curious effect upon the habits of this 

 flattened delicate " Leaf-worm," for it no longer multiplies 

 after the routine manner of its kind through the stages of 

 egg and young, but simply splits into several portions each 

 of which grows into an adult, with a full complement of 

 senses and organs. Plant-browsing animals, such as Snails, 

 are very liable to transportation, and several, such as the 

 West Indian Bulimus octonus, and B. goodalli, have fre- 

 quently been found in British greenhouses, while many 

 years ago Cfaisilia papillaris was detected by Joshua Alder 

 amongst exotic plants at Granton, near Edinburgh. 



I have already said in effect that the more strange in 



