Mabch 23, 1906.] 



SCIENCE. 



469 



water supply is not so limited as is the case 

 with epiphytic orchids. 



In distribution orchids are very local. Few 

 genera are common to both the old world and 

 the new, and when they are common to both, 

 the distribution is a zonal one. The genus 

 Cypripedium^ as at one time understood, was 

 a supposed exception to this. Recent authors, 

 however, basing their conclusions upon well- 

 defined structural differences in the flowers, 

 have divided this, at one time cosmopolitan, 

 genus, into four genera, each of the four 

 genera with a well-defined geographical dis- 

 tribution. We have now, instead of the one 

 big genus, the following: 



Selinepedium, new world, with 3 species, 

 known only from Central America to Brazil. 



Cypripedium, old world and new, but zonal 

 in distribution, with 28 species, north tem- 

 perate. 



Phragmipedium, old world, with 11 species, 

 tropical America only. 



Paphiopedilum, old world, with 46 species, 

 tropical Asia, Malaya, Philippines, etc. 



As genera typical of a zonal distribution, 

 there were mentioned: Cypripedium, Pogonia 

 and Limodorum. Among the genera peculiar 

 to the new world are: Masdevallia, Pleuro- 

 ihallis, Epidendron, Cattleya, Lwlia, Lycaste, 

 Maxillo.ria, Odontoglossum, Miltonia, Oncid- 

 ium and Dichcea. 



Among those confined to the old world are: 

 Thvnia, Coflogyne, Pleione, Ansellia, Phagiis, 

 Dendrohium, Eria, Bulbophyllum, Cymhidium, 

 Phalwnopsis, Vanda, Angrcecum and brides. 



The different features were illustrated with 

 lantern slides, many of them colored. The 

 latter were the work of Mrs. Van Brunt, and 

 were kindly loaned for the occasion by her. 



Alluding to Mr. Nash's discussion of the 

 satisfactory breaking up of the old genus 

 Cypripedium into four genera, and the restric- 

 tion of Cypripedium to its type species and 

 immediate relatives, having a well defined 

 zonal distribution. Dr. Britton remarked upon 

 the wide application of this principle in the 

 progressive study of plants and animals, caus- 

 ing the recognition of very many more genera 

 than were believed to exist by most bot-anical 

 and zoological students in the last century. 



The vastly greater number of species now 

 known, and their more critical comparative 

 study in the field and in collections, as well 

 as the more exact understanding of long- 

 recognized species, show that the number of 

 homogeneous groups which we call genera, 

 existing in nature, is larger than previously 

 supposed. The genus Eahenaria has recently 

 been subdivided into several genera, and this 

 subdivision has been a distinct advance in the 

 taxonomy of orchids. 



C. Stuart Gagee, 



Secretary. 



DISCUSSION AND CORRESPONDENCE. 



A NEW TYPE OP ELECTRIC ORGAN IN AN AMERICAN 

 TELEOST FISH ASTROSCOPUS. 



Jordan in his last book on fishes (1905) 

 mentions that Astroscopus gives an electric 

 shock, quoting Gilbert and others as his au- 

 thorities. He also states that Professor 

 Agassiz and others felt an electric shock from 

 Urophycis regius. Dr. Gilbert, of Stanford 

 University, kindly wrote me, in answer to 

 inquiries, stating that he had felt electricity 

 in Astroscopus, and that another collector had 

 felt it in a Pacific specimen. These facts were 

 mentioned in the bulletin of the National 

 Museum. 



I have examined Urophycis carefully and 

 find no trace of electric organ, but have found 

 that Astroscopus does possess a highly devel- 

 oped if small electric organ. 



It consists of two masses of tissue, one 

 lying behind each eye and extending as an 

 approximately round column from the bare 

 spot on the skin behind the eye down to the 

 roof of the mouth. Like Torpedo it is com- 

 posed of thin electric plates or ' electroplaxes ' 

 that lie in a horizontal position. 



The electroplaxes do not occupy the full 

 width of the column, but are much smaller and 

 overlap and imbricate. Each one is a wide, 

 thin syncytium, markedly different from any 

 form yet described. 



Its neuro-electric surface is smooth and has 

 a thin structureless layer containing very few 

 nuclei. Its other surface is raised into a 

 close-set series of long, evaginated papilla; that 



