1908.] ON A BLOOD-PARASITE OF WHITE MICE. 703 



7, Leucocytozoon mnseuU, sp. n., a Parasitic Protozooii from 

 the Blood of White Mice. By Annie Portek, B.Sc. 

 Lond., Zoological Research Laboratory, Uiiiversitv 

 College, London.* 



[Received May 26, 1908.] 

 (Plate XXXIX.t and Text-figure 154.) 



CONTENTS. Page 



I. Introduction 703 



II. Materials 704 



III. Occurrence of Parasite 704 



IV. Methods 705 



(a) Fresh material 705 



(6) Fixed material 706 



V. General Structure 706 



VI. Movements 707 



(a) Movements of trophozoites 707 



(h) Movements of merozoites 709 



VII. Detailed Morphology 710 



(a) Trophozoites 710 



(b) Vermicules 711 



VIII. Multiplication 711 



(a) Schizogony 711 



(b) Possible Association 711 



IX. Life-History 712 



X. Affinities of the Parasite, and Summary 712 



XI. References to Literature 714 



XIL Explanation of Plate XXXIX 715 



I. Introduction. 



The microscopic organism described in this memoir was found in 

 the leucocytes or white blood-corpuscles of white mice. It is a 

 parasitic Protozoon belonging to the class Sporozoa, and being a 

 blood parasite, it is included in the order Hsemosporidia. As it 

 occurs in leucocytes, it should be placed in the genus Leuco- 

 cytozoon. Similar parasites have been described during the last 

 three or four years from the leucocytes of dogs, rats, palm- 

 squirrels, and cats among mammals, and a few from other 

 Vertebrates. These will be briefly considered at the end of this 

 memoir. So far as I know, such a parasite has not been recorded 

 previously from the mouse. 



As the parasite is shaped like a Gregarine, it is closely related 

 to the genus Hceinogregarina, and some authorities, as Laveran 

 and Mesnil, would place the Leucocytozoa in that genus. I 

 prefer, however, to retain the generic name Leucocytozoon, and 

 since the parasite occurs in the mouse, Mus muscidus, I propose 

 the specific name " muscidi " for it. This creation of a new 

 species is made, not with the intention of merely multiplying 

 species, but to avoid confusion with the parasites found in rats. 

 The nomenclature of these parasites of rats is in a very confused 



* Communicated by H. B. Fantham, D.Sc, A.R.C.Sc, F.Z.S. 

 f For explanation of the Plate, see p. 715. 



Proc. Zool. Soc— 1908, No. XLY 45 



