414 



SCIENCE 



[N. S. Vol. L. No. 1296 



of this interesting medusa in this country, 

 and in the Biological Bulletin of April, 1908, 

 described in some details the history of the 

 case, and evidence of its identity with 

 Limnocodium sowerlii of Europe. These 

 ■were the first accounts of this species in the 

 IJnited States, and its occurrence at that 

 time in the aquarium of a green-house in 

 Washington, D. C, used by its owners for 

 propagating exotic tropical plants, suggested 

 its possible introduction by means of such 

 plants. But the assurance of the proprietor 

 that only the seeds of such plants were im- 

 ported threw serious doubt upon such an in- 

 ference. 



In Science, December 15, 1916, Professor 

 H. Garman reported a most interesting occur- 

 rence of this medusa in Benson creek near 

 Frankfort, Kentucky, and later the present 

 writer received from Professor Garman speci- 

 mens which were identified as the same as 

 those formerly described from the Washington 

 aquaria. Here in this fresh-water stream, a 

 small tributary of the Kentucky river, far re- 

 moved from any possible source of artificial 

 introduction, the occurrence of "millions" 

 of these medusis, at once utterly discredited 

 the earlier asumption of distribution by arti- 

 ficial means from tropical sources of its 

 assumed habitat. 



On October 4, 1919, I received from Pro- 

 fessor F. Payne of Indiana, a letter an- 

 nouncing the finding of these medusse in a 

 lake in northern Indiana, and on the follow- 

 ing day an official communication from the 

 Bureau of Fisheries announcing its receipt 

 from " Boss Lake " near Elkhart, Indiana, of 

 medusae presumed to be the same as those 

 formerly described from Washington, D. C, 

 and later from Kentucky, as cited in the 

 above paragraph, and this was easily verified 

 on the receipt of excellent specimens pre- 

 served in formalin. These were accompanied 

 by copies of letters from Mr. J. C. Boss, 

 owner of the small lake mentioned above. 

 This lake was constructed by Mr. Boss, and 

 the following abstract from his letter to the 

 Commissioner of Fisheries will be interesting. 



Boss Lake resulted from the overflow caused by 

 the building of a large dam on the St. Joseph 

 Eiver. Our family owned and operated a brick 

 yard at a point on said stream the backwater of 

 which flooded so large a portion of the clay bank 

 that it ruined it for commercial purposes. A 

 large dyke was built between the clay pit and the 

 river, reinforced by puddled clay to make it as 

 nearly as possible water tight so we might raise 

 the water to a height of about seven or eight feet 

 above flood tide of the river; this purpose was 

 accomplished effectively and the lake so stands 

 to-day. The lake contains about four acres, is fed 

 by surface spring water and an artesian flowing 

 well, the level remaining constant. 



This lake has been stocked with Black Bass 

 supplied by the Bureau of Fisheries, and Mr. 

 Boss states " there have never been any 

 plants from other lakes introduced or planted 

 in this, especially not of exotic species," 

 though it abounds in native aquatic grasses, 

 he states. 



A most interesting feature comes to light 

 in the data furnished by Mr. Boss, namely, 

 that the medusse were first observed one year 

 ago, then very few in number. This year 

 about August first they again appeared and 

 in greater numbers, and during " ten days we 

 have seen millions, they come to the surface 

 on warm sunshine days." That is, not only 

 have these formerly supposed tropical medusae 

 established themselves in northern waters, 

 and persisted over winter, but have greatly 

 multiplied during the second year, hence 

 breed freely under these conditions. Those 

 found in the Kentucky creek apparently dis- 

 appeared very suddenly, as did those in the 

 Washington aquaria as reported in my former 

 papers, on the approach of cooler weather ; and 

 in neither of these localities have they reap- 

 peared, so far as known. Professor Garman 

 stating his purpose to closely follow up the 

 matter the following year having made no 

 further report. 



These several occurrences of this medusa 

 in the fresh waters of this country clearly 

 proves that it has become an indigenous 

 faunal factor and clearly able to perpetuate 

 itself, and further that it has not at any 

 time been introduced through artificial means 

 from remote regions. It still remains prob- 



