ALGUNOS DETALLES ACERCA DE LOS NUCLEOS CELULARES ESTUDIADOS POR MEDIO DE LA REACCION DE FEULGEN Y PARTICULARIDADES ESTRUCTURALES DE LAS ESPICULAS DE LAS ESPONJAS DEL LAGO DE XOCHIMILCO

Resumen

The author gives a brief description of the two principal species of fresh water sponges of the Lake of Xochimilco, Ephydatia subdivisa and another species of the same genus which he provisionally names Ephydatia viridis. He also indicates some of the details of their biology and symbiotical phenomena. He
exposes two particular points of investigation, the comparative study of the structure of the nuclei of the ecto-meso-and endodermical cells, describing in detail their respective pecularities. This study was complished by means of Feulgen nuclear reaction which, so far as the author is informed, is applied for the first time to the study of che fresh water sponges.
Another point of the author's investigation is the description of a peculiar structure of the spicules of Ephydatis subdivisa. Applying a strong heat to the spicules he discovered that a spicule is really made up of two parts, an inner one which is a kind of tube with heat resistant walls which only curve but do not swell, and an outer cortical layer which is less heat resistand and swells forming a kind of ampule, the above described structures being a quite new detail about the silicious spicules of the fresh water sponges.