48 THOMPSON YATES LABORATORIES REPORT 
In the blood of one native, a court messenger at Degema, we found on very 
many occasions an embryo similar to that of F. perstans in its movements, general 
shape, and appearance, but longer (average in stained specimens i 5 1 m)- Four spots 
in stained specimens were made out, and were more distinctly marked than in the case of 
the ordinary F. perstans. 
1. A constant narrow transverse band at a distance of 24*2 per cent, of 
total length from the anterior end. 
2. A small lateral bay at distance 32-4. Fairly constant. 
3. A distinct small area, in which the cells are loosely arranged, at 
distance of 61 "2. This is only occasional present. 
4. A small bright spot, sometimes lateral, sometimes central, at 8i"2. 
Filaria demarquaii 
The embryo only of this worm is known. It is thus described by Manson" 
who observed it in specimens of blood from natives of St. Vincent, West Indies, in 10 
out of 1 50 examined. ' It resembles F. nocturna and F . diurna so far as shape is 
concerned, but differs from them in size. I have had no opportunity of making 
trustworthy measurements of living specimens in suitably prepared slides, but judging 
from rough preparations, F. demarquaii appears to be rather more than half the size 
of F. nocturna and F. diurna. It is sharp-tailed, like these, but in addition to the size 
it differs from them inasmuch as it observes no periodicity, being present in the 
peripheral circulation both by day and by night, and, also, in not being enclosed in a 
sheath. Nothing is known of its life history, minute anatomy, or pathological 
bearings. Possibly it is the embryonic form of F. magalh'desi — also a tropical 
American blood parasite. I have recently met with apparently the same parasite 
in the blood of natives of St. Lucia, West Indies, where Dr. Galgey has still 
more recently shewn that either it, or a similar blood-worm, is very common. It 
is quite possible that the sharp-tailed filaria ( F. ozzardi) of British Guiana is the same 
species. I have also found a minute, non-sheathed, sharp-tailed embryo filaria in the 
blood of natives of New Guinea, likewise closely resembling F. demarquaii. Whether 
these various embryos belong to one or to several species it is impossible to decide 
until the parental forms of each have been discovered and compared.' 
Filaria ozzardi 
A single adult female and a portion of the male found in the subperitoneal 
tissues in the anterior abdominal wall of an aboriginal Demerara Indian by 
Daniells, 1 whose blood contained nematode embryos similar to those to which 
1. Manson, Tropical Diseases. London, 1900. P. 533. 
2. Daniells, British Medical Journal, June 17, 1899. 
