May 9, 1902.] 



SCIENCE. 



747 



Yxicatan coast. Tlie Ciclilidse are a family 

 of fresh water fishes much resembling super- 

 ficially our sunfishes (Centrarchidse), and their 

 occurrence in salt water had not been pre- 

 viously noted. 



The discovery of a new species of catfish 

 belonging to the genus Gonorhynchos, in the 

 Rio TJsumacinta was also reported. No 

 species of this genus was previously known 

 from any point north of Brazil. 



But the most interesting thing in connec- 

 tion with this bagre was the discovery that it 

 has the habit of oral gestation, a curious habit 

 not previously known to be possessed by 

 Conorhynchos, though long known among 

 species of South American and Ceylonese 

 catfishes of the genus Arius. 



When the eggs are laid they are taken up 

 by the male catfish', who retains them in his 

 mouth until they are hatched. 



In the mouth of one of these catfish Mr. 

 Nelson found thirty-nine eggs many of which 

 readily rolled out when the fish was held up 

 by the tail. 



The eggs are quite large, measuring about 

 three-quarters of an inch in diameter, and the 

 embryos are well developed. 



Another important discovery was the fact 

 that GirardinicMhys innominatus is ovovivip- 

 arous. This is a species of Poeciliidae (killi- 

 fishes) and was found by Dr. Rose to be an 

 abundant inhabitant of the Rio Lerma. Its 

 viviparity had not been noted before, nor was 

 the species known to occur elsewhere than 

 about the City of Mexico. 



W. W. Cooke spoke on 'Some Untenable 

 Theories of Migration,' stating that there 

 were two theories as to the relative positions 

 held by the individuals of a given species of 

 bird in their winter home as compared with 

 their positions during the breeding season. 

 According to one theory the relative positions 

 were the same, the birds moving southwards 

 as one body, while according to the other 

 theory the relative positions were reversed, 

 those individuals which bred at the extreme 

 north of the breeding range passing over the 

 others, thus becoming the southernmost birds 

 during the winter. 



The Maryland yellow throat was given as 



an example of this latter method of migration, 

 those individuals that breed farthest north 

 going the farthest south in winter while the 

 southern breeding birds remained almost 

 stationary. But even here a complete re- 

 versal of position does not take place, for the 

 intermediate breeding birds do not winter so 

 far south as the southern breeder. 



The red-winged blackbird, it was stated, did 

 not follow either of the so-called rules and, 

 in fact, each species seems to have a method 

 of migration peculiar to itself, so that no gen- 

 eral rule could be laid down that would cover 

 even a large proportion of the different species. 

 In most species, however, a reversal of posi- 

 tion does occur during the early spring mi- 

 gration, but this condition does not last long. 

 F. A. Lucas. 



THE ELISHA MITCHELL SCIENTIFIC SOCIETY. 



At the 141st meeting of the Society, at the 

 University of North Carolina, on April 15, the 

 following papers were read : 



' Arsenic Pentachloride ' : Mr. H. H. Bennett. 



' Copper Deposits of North Carolina ' : Dr. J. H 

 Pratt. 



' Price of Chemicals ' : Dr. Chas. Baskerville. 



' Non-cellular Differentiation in Embryos ' : Dr. 

 H. V. Wilson. 



Chas. Baskerville, 



Secretary. 



DISCUSSION AND CORRESPONDENCE. 



SCIENTIFIC TEEMINOLOGY. 



The word 'ecology' is not to be found in 

 recent English dictionaries, no doubt because 

 such dictionaries do not profess to include 

 every vagary of incorrect spelling that may 

 find its way into print. But had Mr. Horace 

 White looked up 'oecology,' he would have 

 found it in the best dictionaries of the last 

 fifteen years at any rate. He would not, how- 

 ever, have found the definition that is now 

 given by you, but — to quote the 'Century 

 Dictionary' — "The science of animal and 

 vegetable economy; the study of the phenom- 

 ena of the life-history of organisms, in their 

 individual and reciprocal relations; the doc- 

 trine of the laws of animal and vegetable ac- 

 tivities, as manifested in their modes of life. 

 Thus, parasitism, socialism, and nest-building 



