638 



SCIENCE 



[N. S. Vol. XXVI. No. 671 



of fishes from Yucatan, we stated that Heros 

 affi.nis and Heros urophthalmus had appar- 

 ently been reported previously only from Lake 

 Peten, Guatemala. In some unaccountable 

 manner we overlooked, at the time of writing 

 our paper, the report by Evermann and Golds- 

 borough,' published in 1902, upon fishes col- 

 lected in Mexico and Central America. Dr. 

 Evermann has kindly called my attention to 

 the fact that the species mentioned were both 

 obtained in Yucatan by Mr. E. W. Nelson, as 

 recorded in the paper referred to. It so hap- 

 pens that Mr. Nelson had specimens from 

 exactly the same places that I obtained them, 

 namely, H. affinis at Progreso and H. uroph- 

 thalmus at Progreso and at Chichen-Itza. 

 Some of my specimens apparently came even 

 from the same watering trough at the latter 

 place, but I was successful in obtaining them 

 directly from both the Great and Sacred 

 Cenotes as well. 



In the same connection it is interesting to 

 note that " Mr. Nelson heard that cat-fish 

 occur in a well [cenote] at Chichen-Itza, but 

 did not see any specimens " {loc. dt., p. 138). 

 From the Sacred Cenote I obtained two speci- 

 mens of one species of catfish, and from 

 another cenote, some three or four miles to the 

 eastward, eleven examples of another. Both 

 of these appeared to be new, and have been de- 

 scribed and figured by Mr. Barbour and myself 

 as Rhamdia sacrificii and Rhamdia depressa, 

 respectively. 



One would not have suspected the presence 

 of these catfishes in the Sacred Cenote, as they 

 ■were at no time seen swimming about. The 

 two specimens described were obtained for me 

 by the Indians, upon hooks baited and sunk 

 to the bottom. At the other cenote mentioned, 

 however, the catfish were much in evidence, 

 swimming about in a large school near the 

 surface. As Mr. Nelson probably did not visit 



Pisces," Bull. Mus. Comp. Zool., Vol. 50, No. 5, 

 pp. 146-159, pis. 1 and 2, 1906. 



"Evermann, B. W., and E. L. Goldsborough, 

 " A report on fishes collected in Mexico and Cen- 

 tral America, with notes and descriptions of five 

 new species," Bvill. U. S. Fish Com. for 1901, pp. 

 137-159, 1902. 



this cenote, these facts may explain why he 

 did not see catfish at Chichen-Itza. I do not 

 understand, however, why he did not see the 

 mojarras (Heros urophthalmus) in the cenotes 

 when he was there in February, as I saw them 

 commonly during the whole period of my 

 stay from February 13 to April 9. Further- 

 more, I found that they were not especially 

 difficult to catch, in spite of the fact that I 

 had to resort to boyhood's method of using 

 a bent pin for the purpose, not having suitable 

 hooks at hand. 



It would be interesting to know whether 

 there is any basis for the belief of the natives 

 that the fish disappear from these cenotes dur- 

 ing certain seasons, as it would furnish evi- 

 dence as to the existence of the supposed 

 underground connection of these curious 

 water-holes. On the one hand, unless there are 

 such connections, it seems hard to account for 

 the apparently general distribution of Heros 

 urophthalmus throughout the peninsula (un- 

 less we take into account the possible assist- 

 ance of human agency) ; while, on the other 

 hand, the segregation of two species of cat- 

 fish in two cenotes only three or four miles 

 apart is difiicult to explain if there do exist 

 subterranean connections of any considerable 

 size. Leon J. Cole 



OCCURRENCE OF THE FRESH-WATER MEDUSA, 

 LIMNOCODIUM, IN THE UNITED STATES 



On August 17, the writer received at the 

 laboratory of the Bureau of Fisheries, Woods 

 Holl, a few medusae with the request for their 

 identification. They had been sent from 

 Washington on the fifteenth in a small bottle 

 and were living when received and continued 

 to live for more than a week, though gradually 

 declining. 



A cursory examination showed them to be 

 a species of the fresh water medusa, Limno- 

 codium, the occurrence of which in consid- 

 erable number in Regents Park, London, in 

 1880 marked our first accurate knowledge 

 concerning a medusa of this habitat. It was 

 described by both Allman and Lankester, and 

 its characteristics and something of its life 

 history critically observed. 



