242 CYSTICERCOOIDS PARASITIC 



nature, so that their discovery is frequently more the result of 

 accident than design ; second, owing to the minuteness of the 

 creatures in question, and in consequence of their not forming 

 cysts, or true bladders, like their congeners, the Cestodes, they are 

 frequently overlooked, and their discovery is somewhat of rare 

 occurrence. 



At intervals during the past (qw years, I have been engaged 

 in exploring the ponds and ditches in my neighbourhood, Canter- 

 bury, for the Cyprides, with a view of determining the different 

 species that exist in this part of Kent ; to discover, if possible, 

 their habitat, and hoping to find undiscovered males, as well as to 

 become acquainted with certain Infusorians, which serve as hosts 

 to these minute Crustaceans. 



To discover the males, and to become acquainted with their 

 structure, it is necessary to crush the shell of the crustacean and 

 tease out its viscera. Under such circumstances, the reader may 

 be sure that a great number of different species have necessarily 

 passed through my hands, or rather under, the dissecting micro- 

 scope, for, as I have said in a former paper on this subject,* it is 

 next to impossible to determine male from female without doing so. 



Among the many specimens of Cypris 77imuta examined, there 

 was one which harboured a peculiar heart-shaped parasite. This 

 was mounted in glycerine for comparison in case others should be 

 found, but it proved a solitary example. About the same time, I 

 gathered from another pond, Reed-pond, some C. viviens, females, 

 and two of them yielded the same kind of parasite in contour, as 

 was previously found in C. mimita. These were similarly mounted. 



In the year 1887, I discovered in this district the male Cypris 

 cme?-ea, and in the course of preparation of a paper on the male 

 organs, a great number were examined, yet during the investiga- 

 tion none of the parasites in question were discovered, but some 

 time afterwards, whilst examining some of the same species of 

 Cypris taken from another pond, I was surprised and gratified to 

 find they not only were the host of a similar Cysticercus to that 

 which had been previously found in C. ini?mia and C. viviens^ but 

 also another and quite dissimilar Cysticercooid. These affected 

 Cyprides were found in a pond destitute of aquatic vegetation, 

 * Journal of Microscopy, Vol. I., N.S., p. 231. 



