ArKiL 28, 1905.] 



SCIENCE. 



G63 



THE BIOLOGICAL SOCIETY OF WASIIIXGTON. 



The 397th regular meeting of the Biolog- 

 ical Society of Washington was held February 

 11, 1905, with President Knowlton in the 

 chair and sixty-eight persons present. Mr. 

 Vernon Bailey exhibited a large mussel shell, 

 about 13 X 8 em. in size, from Trinity River 

 in southeastern Texas. He noted that the 

 species is a common food for raccoons. He 

 stated that many pearls are gotten from the 

 region mentioned, and that one had sold for 

 sixty dollars. Dr. L. O. Howard called at- 

 tention to the first authentic record from the 

 Pacific coast of Mexico of the presence of the 

 yellow fever mosquito {Siygeomia fasciata) 

 in this region. The authenticity of the record 

 rests in specimens sent to Dr. Howard by a 

 physician. 



The first regular paper of the evening was 

 by Dr. Albert Mann on diatoms. The speaker 

 introduced his subject by referring them to 

 the Conjugata> of the green algte, and gave 

 several reasons for this systematic position. 



He then took up their distribution, stating 

 that they are to be foimd in all latitudes and 

 all waters, fresh, brackish or salt ; that the 

 tropical are the largest and most ornamental, 

 but they are most j^rolific in individuals in 

 arctic waters. Geologically he placed their 

 first appearance in the Upper or Middle Cre- 

 taceous, stating that the claims of Castracane 

 and others of their presence in the coal meas- 

 ures or even lower are inconclusive. Many 

 of the great beds of diatom earth were re- 

 ferred to. 



The box-like structure of these algae was 

 next illustrated by drawings and the elaborate 

 ornamentation of the valves described. Out- 

 side of this silica case the organic pellicle, er- 

 roneously called a ' gelatinous ' sheath, and in- 

 side the case the large symmetrical chloro- 

 plasts, the cytoplasm, nuclei, vacuoles and oil 

 globules were explained by diagi'ams. 



Under the physiology of the diatoms the 

 speaker explained the normal processes of 

 plant assimilation and stated that their de- 

 pendence on sunlight precluded their being 

 found living in subterranean waters or deep- 

 sea beds; the limit of the latter he placed at 

 100 fathoms. Saprophytic diatoms, Nifzschia 



putrida and Nitzschia paradoxa were men- 

 tioned, the latter semi-saprophytic. 



The multiplication of the diatoms by fission 

 was illustrated by several diagrams and the 

 consequent progressive reduction in size com- 

 mented on. Se.xual reproduction, by which 

 the full dimensions were regained, was then 

 described and illustrated, three variations in 

 method being mentioned. 



The mystery of diatom movement was dis- 

 cussed and the various theories explained. 



Dr. Mann closed his paper by briefly enu- 

 merating the economic uses of the diatoms and 

 by a short description of methods of collection. 

 He then exhibited forty-one lantern slides pre- 

 pared from the negatives of the Hon. A. A. 

 Adee, assistant secretary of state. 



The second paper was by Dr. Edgar A. 

 Mearns, on the ' Animal Life of Mount Apo, 

 of the Philippine Islands.' He said, as the 

 result of a month's examination of the 

 solfataric volcano Apo, the giant of the archi- 

 pelago, its animal life became sufficiently 

 familiar to admit of at least a partial com- 

 parison with that of the better explored moun- 

 tains of Luzon and other islands of the Philip- 

 pine group. The constituent fauna of Mount 

 Apo partakes largely of peculiar elements, 

 which isolate it not only from the lowlands of 

 Mindanao, but from the highlands of other 

 Philippine islands, and give it a faunal posi- 

 tion comparable in importance to that of 

 Monte Data in Luzon and Kina Balu in 

 Borneo. Several of the genera and most of 

 the species of manmials collected on the higher 

 portion of Apo are new to science; and three 

 genera and more than a score of species of 

 birds have been recently added to the Philip- 

 pine avifauna from Mount Apo. Dr. 

 Stejneger has recently described two new 

 species of frogs and one new Gecko from the 

 speaker's Mount Apo collection. 



The 398th regular meeting of the society 

 was held February 25, 1905, with President 

 Knowlton in the chair and thirty-seven per- 

 sons present. Under Notes, Dr. C. E. Waters 

 referred to the paper of the preceding meet- 

 ing by Dr. Mann, on diatoms, and to papers 

 by Kramer and White, and asked if it were 



