MALARIA EXPEDITION TO NIGERIA 51 
smaller. The fifth is much smaller than the other, and is conical and sharp pointed. 
There are two slender, unequal spicules. The cuticle is not obviously straited but 
is dotted over with a number of widely scattered nearly hemispherical smooth bosses. 
No definite arrangement of these bosses could be made out. The large bosses are at 
the middle of the worm. The internal structure could not be made out.' 
The life history of F. loa is quite unknown. Manson suggests that it is the 
parent form of F. diurna. 
Of the embryos, Manson 1 says: — 'The more mature embryos resemble in 
size and shape those of F. nocturna and F. diurna, but in consequence of the method 
of mounting it is impossible (speaking of the particular specimen under examination) to 
say if they are possessed of a sheath or not. If they are possessed of a sheath, I 
should say that they are practically indistinguishable from the parasites mentioned.' 
Leuchart states that the embryos of F. loa 'are enclosed in thin egg shells, and bear 
a close resemblance to F. sanguinis, but are smaller (o - 2 1 mm.)' 
Our experience of the few cases of F. loa which we met with during the 
expedition accords with that of Manson, in that an examination of the blood day and 
night did not reveal the presence of filaria embryos. We have, however, recently 
received a female specimen of F. loa, removed from the eye of a Kroo boy by Dr. A. 
H. Hanley, medical officer at Opobo, Southern Nigeria. An examination of the 
blood showed the presence of embryos. We have counted the embryos on four 
slides taken at different hours of the dav and night which were sent with the adult 
specimen. 
At 10 a.m. the blood preparation contained seven embryos 
„ 3 p.m. „ „ „ nine 
„ 9 p.m. ,, ,, „ no ,, 
„ I 1 p.m. „ „ ,, one ,, 
These figures point to an infection with F. diurna, but the examinations being 
so few, in the light of the results of examinations of other cases, a very definite 
opinion cannot be given. 
Dr. Hanley also sent a specimen of a male F. loa removed also from the eye 
of a Kroo boy whose blood contained no embryos. We were fortunate enough to 
obtain at Bonny a single female of this species for our collection, and on breaking 
the worm across after preservation in formalin, sheathed embryos very similar to 
those of F. diurna were extruded from the broken ends of the worm. These 
embryos, extruded by pressure from the body of the uterus of a formalin preserved 
specimen, measured 208*5 (*■ l° n g 011 an average, and have a distinct sheath, in 
fact, they appear similar to the embryos of F. nocturna. In stained specimens they 
measure iqc^/x long. (It must be noticed that these embryos had been fixed in the 
1. Manson, Trans, of Ophthalm. Soc. London, 1895. Case of Filaria loa, by Argyll Robertson. 
