1104 ON A NEW HiEMOGREGARIXE. [DeC. 10. 



Avhich stands in need of supjDort, for it is quite conceivable that 

 the same species of parasite might infest several species of hosts, 

 and even that the difference of hosts might cause it to appear 

 under forms more or less different .in different cases. To regard 

 parasites as being necessaiily of distinct species because they 

 occur in distinct hosts is, in reality, not more warranted 

 than the procedure of those naturalists who give distinct names 

 to animals occurring in different geographical regions, even if 

 they do not differ in any other characters, thus begging the 

 question of their specific distinctness. It must be understood, 

 therefore, that the name given to this jjarasite must be 

 considered as purely provisional and liable to be cancelled, that 

 is merged in some older name, with increased knowledge of these 

 parasites. Names given to parasites distinguished, in the first 

 instance, by the specific distinctness of their hosts must not be 

 taken as necessarily denoting distinct natural species (though this 

 will be true of them in the great majority of cases), but merely, 

 so to speak, as labels affixed to certain classes of objects, whei-eby 

 they become represented by parts of speech and can be referred to 

 briefly. 



So many species of hfemogTegai^ines are noAv known from 

 various animals that it is almost necessary to apologise for adding 

 another to the list ; I do so with the object of drawing attention 

 to it in the hope that someone may be brought thereby to study 

 its complete life-history. In the present state of our knowledge, 

 it is not new species of hfemogregarines that are needed, but 

 rather new facts about old species. 



EXPLANATION OF THE PLATES. 

 Plate LV. 



Figs. 2-7, ] 0-12, & 14 are drawn from slide A ; all other figures on tlie Plate are 

 from slide B. All the figiires are magnified 2000 linear. 

 Figs. 1-5, .young intra-corpuscular forms. 

 Figs. 6-8, full-grown intra-corpuscular forms. 

 Fig. 9, vermicule in the act of leaving the corpuscle. 

 Figs. 10-15, free vermicules. 



PlATE LVI. 



Figs. 16, 17, 19, & 22 are drawn from slide C ; all others from slide D. All the 

 figures are magnified 2000 linear. 



Fig. 16, corpuscle infected with two parasites. 

 Figs. 17-21, intra-corpuscular parasites. 

 Figs. 22, 23, free vermicules. 



Lister Institute of Preventive Medicine, 

 15th Nov., 1907. 



