Februaky 23, 1900.] 



SCIENCE 



313 



BIOLOGICAL SOCIETY OF WASHINGTON. 



The 317th meeting was held on Saturday, Jan- 

 uary 27th. William Palmer exhibited a series 

 of specimens of the Christmas Fern, Polystichum 

 acrostichoides, showing variations in growth due 

 to varying conditions of environment. H. J. 

 Webber showed a portion of one of the nega- 

 tively geotropic roots of the mangrove, Rhizo- 

 phora mangle, stating that their function, like that 

 of the ' knees' ofthecypress was that of aeration, 

 and illustrating his remarks with photographs. 



Thomas A. Williams presented some ' Notes 

 on a New Species of Lecidea from Mexico,' 

 stating that it was related to L. speirea Nyl. 

 It is peculiar on account of its Lecanora-like 

 fruit, the apothecia presenting a white border 

 when young and being borne on slight elevations 

 of the thallus, after the manner of the species 

 of Bseomyces with sub- sessile fruits. In some 

 instances gonidia were found in the apothecia, 

 but their occurrence seemed to be accidental 

 rather than normal. The bearing of these 

 structural peculiarities on the systematic rela- 

 tionship of this and other Lecideas was discussed. 



Barton W. Evermann made ' Some Observa- 

 tions concerning Species and Subspecies', bas- 

 ing his remarks upon the species of darters 

 found in the waters of Lake Maxinkuckee and 

 a new species found in Aubeenaubee Creek, the 

 principal tributary of the lake, but not in the 

 lake itself This fish is evidently derived from 

 Etheostoma ioivse, which is found in the lake, but 

 differs from it clearly and constantly, and no 

 intergrading forms are known. Should, for 

 some reason the lake species and that from the 

 creek invade each other's habitat and inter- 

 breed, the result would be the production of in- 

 dividuals possessing characters common to the 

 two species and apparently placing them in the 

 relation of species and subspecies, although if 

 this supposed case were definitely known to have 

 occurred, we should regard the individuals as 

 hybrids and the other forms as still distinct 

 species. The speaker reviewed the chief cate- 

 gories of subspecies, concluding that many tri- 

 nomials were in use where a careful examina- 

 tion of the facts would show that the supposed 

 subspecies are really species. The paper will 

 appear in Science. T. W. Stanton, 



Secretary. 



NEW YOEK ACADEMY OF SCIENCE. 

 SECTION OF ANTHROPOLOGY AND PSYCHOLOGY. 



The regular meeting of the Section was held 

 on Monday, January 22d. The first paper of 

 the evening, entitled ' Some Phenomena of In- 

 direct Vision,' was presented by Mr. Clark 

 Wissler. Experiments were made by exposing 

 in the indirect field of vision, while the atten- 

 tion of the observer was fully occupied with ob- 

 jects in the direct field, small letters or nu- 

 merals. The subjects were not conscious of 

 seeing the characters presented in the indirect 

 field, indeed, one of the subjects whose results 

 were reported did not know until several tests 

 had been made that the characters were there 

 at all. In spite of this failure to receive con- 

 scious impressions from the letters and figures, 

 two subjects were found who could by associa- 

 tion, and afterwards by memory, give in a 

 large number of cases the correct numeral or 

 letter. These subjects made their associations 

 in the form of visualized images. Many of the 

 errors made were similar to those made in 

 normal vision. Thus, c was mistaken for o, 35 

 for 55, etc. It was held that the experiments 

 suggest a relation between normal phenomena 

 and the abnormal as seen in the hysterical eye, 

 and that they point out a way to more com- 

 plicated experiments in induced automatic 

 movements. 



Professor J. McK. Cattell presented a paper 

 on ' The Relations of Time and Space in Vision.' 

 He described experiments on the perception of 

 moving surfaces, which show that a time series 

 may be perceived as a spacial continuum, and 

 explained that the same phenomena held in the 

 ordinary vision of daily life. Although the 

 eyes, head and body are in continual movement, 

 and the images on the retina are constantly 

 shifting, the field of vision appears to be dis- 

 tinct and stationary. Thus if one glances 

 along a row of books, images follow one another 

 on each retinal element in rapid succession, but 

 these successive and rapid changes result in the 

 perception of a space continuum, all the objects 

 being distinct and arranged side by side. 



Professor Buchner read a paper on ' Number 

 Forms.' The paper described with the aid of 

 sketches the fixed visualizations experienced 

 since childhood by a woman 35 years of age. 



