KEl’OKT OF TKAVKLLINCi I’ATHOLOGIST AND I'UOTOZOOLOOIST 151 ! 
parasite. The parasite consists of irregular strands of protoplasm on which the chromatin 
is arranged in one or more clumps- -multiplication apparently takes place by a process of 
budding, as in other Dabesice. In lig. 1 is shown a form with four bud-like processes which 
are clearly comparable w’ith the budding which takes place in the case of Babesia canis. For 
this Babesia, which differs ffom the only other species described from small mammals—viz. 
that described by Fantham from the rat and by Nioolle from Ctenodaciyliis fjondi of Tunis--I 
suggest the name Babesia aviciilaris, from its host Avicularis zebra. 
II/JSMOaUEGABINA 
llamogregarina gracilis, n. sp. 
Host, Mabwia quinqueUeniata. Locality, Wau, Bahr-Bl-Ghazal Province 
Plate XII., figs. 17-32; Plate XV., figs. 10, 13 
This curious haemogregariiie, which differs from any hitherto described species, was found 
in the same lizards in which the parasites named Plasmodium mabiiia were discovered. The 
hiEmogregarine has no connection with this last-named parasite, nor with the trypanosome 
which was occasionally found with it. The hsemogr’egarine is remarkable on account of its 
narrowness and the property it has of pushing out the corpuscle at either end, causing it to 
be much elongated. In many cases the corpuscular membrane is drawn tightly over the ends 
of the parasite. The effect is produced of a stiff rod within the corpuscle. It is common to 
find two parasites within one cell; rarely are three present. The parasite lies as a slightly 
curved rod along the long diameter of the cell (Plate XII., figs. 20, 21). Other forms of the 
parasite are met with in the blood, but the great majority ai’e seen as these curved rods. The 
length of the hgemogregarine is IG^* or 17^l, with a breadth of about l'5/i. A delicate cyst 
encloses the parasite, as in other haemogregarines. Within the transparent cyst the parasite 
appears as a narrow' rod of protoplasm, staining a very pale Iffue. The nucleus is elongated 
and occupies about one third the length of the body. Some very fine red granules are often 
seen in the pale blue protoplasm. Sometimes tbe parasites are looped around the nucleus, hut 
in such cases the cyst is also looped, and not the parasite within an unlooped cyst, as is usual 
with other hiemogregarines. 
The cyst, with the parasite within it, may become free in the plasma, and, finally, by 
rupture of the cyst, the hcemogregarine escapes (Plate XII., fig. 17). Empty cysts are often 
encountered in the blood films. Unencysted parasites may also be seen within the corpuscles. 
These are sometimes elongated and like the encysted forms, but more usually they are 
contracted to bodies with an oval or circular outline (Plate XII., figs. 19, 26). 
In the fresh blood the infected cells are seen to be deformed, being more pointed and 
longer than the. uninfected cells. On careful observation the parasites are seen as very pale 
rods lying within the cells. In the fresh blood little of their structure can be made out. 
Occasionally parasites are seen free in the plasma, as very narrow haemogregarines. The 
movements consist of a gliding forwards, a looping and unlooping, and a contraction and 
elongation of the body. From the appearances of the parasites within the cells, either in the 
fresh blood or in stained films, it would be difficult to form an opinion as to their nature, but 
tbe type of movement of the free forms is characteristic. The appearances of the parasite 
within the corpuscle is very constant, with the exception of the occasional occurrence of the 
rounded forms mentioned above. Nothing to be compared with sexual differentiation can be 
distinguished in the blood, 
Hceniogre- 
garines 
A curious 
hajmogre- 
garine of 
lizards 
Encysted 
forms 
Free forms 
