The human transport of animals across the Northern Atlantic 171 



is at least partly due to the fact that the Panama Canal was not opened until 

 1914. 



Hatch (1949) has made intense investigations of the greenhouse fauna in Wash- 

 ington, Oregon, and British Columbia, and found it surprisingly rich. Not only 

 the obligatory terrestial Isopods (Wood-lice) but also insects, especially Coleoptera, 

 were strongly represented, in part by species not regularly confined to this kind 

 of habitat, among these several Europeans, as marked in the list above. Hatch 

 (I.e., p. 162) is certainly right in his conclusion: "To the extent to which green- 

 house species are introduced, it is probable that the shipment of nursery stock and 

 other plant materials have played an important if not exclusive role in their 

 dispersal. And some of these species may first have found their way into this 

 country through the medium of greenhouse shipments" (cf. also below, p. 216). 

 This applies also to a surprisingly large number of European indoor Spiders 

 (genus Theridium and others) found exclusively in the Pacific Northwest [vide list, 

 p. 94 a.f.). 



However, there are also other European introductions in the Northwest, 

 seemingly without any connection with greenhouses. Most of them occur also in 

 northeastern North America (for examples, vide p. 138) and are there regarded 

 as having arrived with ballast. Some of them may have reached the Pacific coast 

 by subsequent transcontinental dispersal, either actively or with man, but others 

 apparently are completely isolated in the Northwest. It seems reasonable to sup- 

 pose that at least the majority of them has reached also this region by ballast 

 transport and probably, in spite of the distance, directly from Europe. 



In order to get an idea of to what extent ballast was used in this trade, I contacted 

 the officials of the foremost ports of the Pacific Northwest and recieved two answers 

 of considerable interest. 



The first was from Tacoma, Wash., forwarded by Miss Elfriede Gudelius of 

 the Public Library, indicating that in sailing ship days, when big square-riggers 

 arrived on Puget Sound from foreign ports to load wheat and lumber, they were 

 often in ballast. 



The second reply was from Portland, Oreg., and sent by the General Manager 

 of the port, Mr. J. J. Winn, Jr., who, referring to a letter from his predecessor in 

 office, quotes as follows: 



"In the old days, ending with World War I, sail vessels came in ballast to load 

 wheat (mostly) for Europe. They all discharged earthen ballast— usually rocky 

 stuff or sand which the stevedore companies removed and dumped into low lands 

 abutting on the river. For many years the 'ballast' dock was in the vicinity of the 

 present Terminal I; later it was in the Linton area in the vicinity of the present 

 Gasco plant, as I recall." 



