Excerpt from The Saprolegniaceae: With Notes on Other Water Molds

In Leptolegm'a, Petersen (ann. Myc. 8: 522. 1910) found that the spores were linked together by their cilia on passing through the sporangium. Mr. Couch finds that the cilia are formed from the original protoplasmic layers connecting the spore origins while they are against the cell wall, that these threads unless jerked apart by a too vigorous rocking of the spores persist and thus the spores as they emerge are connected with four protoplasmic threads, two in front and two behind. After emerging from the sporangium two Of these four connections persist as cilia, but which two has not yet been clearly demonstrated.

In the case of Achlya, Mr. Couch finds a similar condition. A sporangium of Achlya dubia in the act Of discharging its spores was killed with 1% osmic acid, and the discharged spores instead of forming a close mass at the tip of the sporangium separated a short distance from each other but remained attached in a loose cluster to the tip of the sporangium as if held together by a mucus or by delicate threads of protoplasm. At this moment the sporangium was dragged gently by the observer for a distance of several millimeters. At first the entire mass moved, and then the spores began stringing out, the ones behind being pulled apparently by those in front. A cover glass was then applied and the spores stained with a 1% solution of F uchsin and methyl Violet in 95% alcohol, to which was added three times its volume of water. This stain brought out unmistakable connections Of delicate protoplasmic threads between the spores. Many spores had become separated from the general mass and it was Observed that these connect ing protoplasmic threads were on both ends of some spores, while on other spores the threads were in the normal position for cilia. Furthermore, spores on which these threads occupied all intermediate positions between the above two were observed. Similar results were obtained with A. Con spicua, A. Apiculata and its variety prohfioa, A. Orion, and A. flagellata. Mr. Couch's work on this problem is still in progress and will be published with illustrations in a future number Of the Journal Of the Elisha Mitchell Scientific Society.

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