i8 



RESEARCHES ON FUNGT 



Spinellus fusiger, Mucor plasmaticus, and Sporodinia grandis. 

 There is no evidence that van Tieghem used a camera lucida in 

 making his drawings and, doubtless, he represented the crystalloids 

 shown in his diagrammatic illustration reproduced in Fig. 9 as being 

 larger, relatively to the diameter of the stipe, than they are in nature. 



The Orange-red Pig-ment. — In 1892 Zopf ^ investigated the 

 orange-red pigment which colours the protoplasm of Pilobolus and 

 found that it consists of carotin which is held within minute oil- 

 drops. Zopf expressed the opinion that the carotin is merely a 

 reserve food-substance ; but, as we shall see later, in the mature 

 sporangioj)hore carotin is especially concentrated in the mass of 

 protoplasm which forms a perforated septum at the base of the sub- 

 sporangial swelling and which is intensely illuminated when the 

 sporangiophore is in heliotropic equilibrium. It is therefore possible 

 that the carotin plays some part in the response of the sporangiophore 

 to heliotropic stimuli. 



Parasites of Pilobolus. — The Piloboli, when growing wild on 

 horse dung, etc., are not infrequently attacked by parasitic fungi 

 which may attach themselves to or enter the young sporangiophores, 

 stop their growth, and entirely prevent the production of sporangia 

 and spores. Among these parasites, as shown in the accompanying 

 Table, are species of Pleotrachelus, Piptocephalis, Syncephalis,Mortie- 

 rella, and Dimargaris. 



Parasites of Pilobolus 



1 W. Zopf, " Zur Kenntniss der Farbungsursachen niederer Organismen, No. III. 

 Phycomyceten-Farbungen," Beitrdge zur Physiologie und Morphologie niederer 

 Organismen, Leipzig, Heft II, 1892, pp. 3-12. 



