TRICHOMASTIX SERPENTIS. 449 



Tricliomastix serpentis, n.sp. 



By 

 €. Clinrord Dobcll, B.A., 



Scholar of Trinity College, Cambridge. 



With Plate 27, and 2 Text-figures. 



The subject of this paper is a parasitic flagellate which I 

 have obtained from the rectum of Boa constrictor^ L. 

 Owing to the kindness of Mr. W. A. Harding, of Histon, 

 Cambridge, I was enabled to examine one of these snakes 

 shortly after it had died of canker of the mouth. In the 

 rectum there was about 30 c.c. of a brownish, almost odour- 

 less, alkaline fluid, containing many organic particles in 

 suspension. This fluid was transferred to a glass dish, and 

 pi'evented as far as possible from evaporating by covering 

 with a thick glass plate fixed down by vaseline. It was by 

 examination of this culture from time to time that the obser- 

 vations here recorded were made. 



The first examination was made upon October 30th, 1906, 

 one day after the death of the snake. Tricliomastix was 

 found to be present in small numbers. The parasites in- 

 creased in numbers in the culture, and reached a maximum 

 at the beginning of December, 1906. A decline in the 

 number of the organisms present in the fluid then followed, 

 accompanied by several curious changes in the animals 

 themselves. At the end of February, 1907, there were very 

 few specimens to be found after a very careful search, and 

 by March 2nd, 1907, all the parasites had died out, Alto- 



