Io93-] NEW-YORK MICROSCOPICAL SOCIETY. IS 



of Suriella, Stauroneis phcenicenteron, Terpsinoe musica. But the 

 slide is characterized by the richness of this last species. 



"At least forty years ago Dr. Ehrenberg noted the occurrence 

 of T. musica in the rivers of Texas. But only a year ago it was 

 announced in The Microscope, under the warrant of a leading 

 New Jersey diatomist in his criticism of a popular article in re- 

 gard to the distribution of the various genera, that T. musica was 

 an exclusively marine genus. This statement met with no denial, 

 so far as I am aware of. The park resort at San Antonio derives 

 its name from the San Pedro Springs, which are bold, fresh-water 

 springs flowing from fissures in a cretaceous, fossiliferous stratum. 

 The flow is so great that it is conducted in bridged ditches, or 

 small canals, through the heart of the city of San Antonio, a mile 

 and one-half distant. The little pleasure lake is, of course, fed 

 by these springs. 



" Having placed with the Society two typical representative 

 species or varieties of that American T. musica, a field is presented 

 to diatomists to make a comparative study of this genus, with 

 a view of noting the biological divergence between the Mobile 

 River, Ala., marsh deposit of T. musica, and the San Antonio T. 

 musica. M. J. Tempere, editor of Le Diatomiste, Paris, has al- 

 ready in print critically classed the Mobile marsh species as being 

 more nearly related to T. i/itermedia Pantcschek than to the ordi- 

 nary type of T. musica Ehrbg. 



''2. The other slide sent herewith is derived from an exca- 

 vated lake bottom, the result of cutting a canal, or artificial ' cut- 

 off,^ to reclaim a large area of land subject to periodical inunda- 

 tion, and now to be filled in for railroad station grounds, at Hous- 

 ton, Texas. The lake traversed by the canal once formed a part 

 of White Oak Bayou, and only in the period of high water in the 

 bayou the bayou and lake became coterminous. In low-water 

 periods the lake had a restricted area, containing living mussels, 

 salamanders, etc. Through whatever period the lake may have 

 survived, it became the receptacle for many kinds of microscopic 

 vegetable remains and seeds, as well as a diatom deposit, sur- 

 rounded on all sides by barren red and white, silicious, sandy 

 strata. 



" The slide, while containing hundreds of frustules, was predi- 

 cated upon the examination of a dry clod of the earth, on the sur- 



