Damping Off. 319 



Btraight chains, or they may form a curve, or again a short and 

 close spiral so that they are held close to the point of origin in a 

 small head. 



The conidinm may be spherical or broadly apiculate at the proxi- 

 mal end or more minutely apiculate at the distal end. Sometimes 

 there is no enlargement of the fruiting thread at the point of origin 

 of the conidium, but very frequently, and in a majority of cases 

 whicli I have observed where they are grown in water, there is an 

 oval enlargement of the hypha with a minute apical sterigma which 

 bears the conidium. AVhere there is quite rapid growth of the 

 fungus the hypha grows onward pushing the recently developed 

 conidium to one side, but not always freeing it, and soon bears 

 another conidium in like manner. This continues so that several 

 conidia may be borne at short intervals on the same branch, and the 

 successive points of the origin of the conidia are not only marked 

 by tho attached conidia but by the oval enlargements on the branch. 

 The appearance is thus, in many cases, very much like that of the 

 conidiophores of Phytopldliora^ and de Bary has called attention to 

 the same fact. Many of the conidia become free. 



Early in April of the same year cultures were again started on 

 glass slips in water. A preparation was started Tuesday afternoon, 

 April loth, at 3 p. m. At 6 p. m. considerable growth had taken 

 place and several conidia were developed. At 9 p. m. another 

 examination was made and quite a profuse growth was present and 

 numerous conidia or zoosporangia. 



At 9 a. m., April 11th, there were many free conidia and zooepor- 

 auffia and the culture abounded in the form of fructification which 

 so closely resembles Phytopliihora. Fresh water was now added to 

 the preparation, a cover glass placed upon it for the purpose of 

 studying it with the high power of the microscope and for obtaining 



Explanation of Plate II. Artotrogus intennedius (de Bary). 



Fif^s. 10, M, 12, 13, conidia developed in chains. 



Figs. 14 and 15, conidia borne in-a mannerreseuibliugtbeconidial fructification 

 in Pbylophthora. 



Figs. 17-23, different stages in the development of the zoospores. 



Fig. 24, free zoospores with a ciliuin at each pointed end, passing into amoeboid 

 movement and becoming divided into oval uuciliated zoospores. 



Fig. 16, intercalary eonidinm. 



All the figures from camera lucida drawings and magnified fifty times more 

 than the scale. Scale 1 millimeter. 



