26 
PACIFIC SCIENCE, VoL V, January, 1951 
vagina of gravid female worms (Table 4). The 
shell had a smooth surface with no discerni- 
ble markings. 
Ransom (1904) obtained embryonated eggs 
from the uteri of gravid worms. These were 
placed in ''salt solution'’ and were reported to 
have hatched in 3 days. The larvae obtained 
were dead, or were feeble and soon died. 
Sanders (1928) employed a similar technique, 
substituting distilled water for the saline 
solution, and found that embryonated eggs 
from gravid females hatched in 3 days. 
Fielding (1927) succeeded in hatching liv- 
ing larvae in the following media: 0.9 per cent 
NaCl, 1.4 per cent NaCl, other physiological 
solutions, 1 per cent citrated fowl blood,, 
moistened earth, fowl feces (plus sand and 
saline), sterile fowl feces (plus saline and 
charcoal), moistened bread. Hutson (1943) 
was unsuccessful in hatching eggs in distilled 
water but obtained living first-stage larvae 
from cultures of distilled water plus fowl 
feces. Upon introduction into the body cav- 
ity of a roach these larvae developed normally. 
It seemed desirable to determine, if possi- 
ble, whether eyeworm eggs hatch more readily 
in the digestive tract of the intermediate host 
or in fowl feces. Attempts were made to ob- 
tain mature eggs from the crops of infected 
chickens. (Some embryonated eggs obtained 
from the uteri of gravid worms may not be 
fully matured. Such eggs in other species of 
nematodes have been known to "hatch” ab- 
normally in artificial media.) Although eggs 
were usually present in the crop, they could 
not be separated in sufficient quantity for the 
experiment. This made it necessary to obtain 
embryonated eggs from macerated female 
worms. To avoid as far as possible the selec- 
tion of immature eggs, special care was taken 
to collect by use of a fine pipette only the 
largest eggs. 
These were placed in three dishes contain- 
ing (1) physiological saline solution, (2) 
physiological saline solution plus sterilized 
fowl feces, and (3) physiological saline solu- 
tion plus the macerated alimentary tracts of 
several Surinam roaches. None of the eggs had 
hatched by the end of the second day, but 
quiescent or feeble larvae were observed in 
each of the three cultures on the third day. 
None of the larvae survived. Although addi- 
tional work is indicated, apparently, under the 
conditions of this experiment, the medium 
had no appreciable effect upon the rapidity 
with which eyeworm eggs hatched. 
Larvae observed both in the artificial media 
and in the alimentary tract of the intermedi- 
ate host apparently hatched in the following 
manner. (The terminology used is based on 
the description of the spirurid egg by Chris- 
tenson in Chitwood et al., 1940.) The chitin- 
ous middle layer of the shell separated from 
the inner vitelline membrane at either or both 
poles. The region of the poles then became 
thinner, producing polar operculations marked 
by ill-defined sub-terminal lines of fracture. 
One or both caps either broke off at the line 
of fracture or dissolved, leaving a barrel- 
shaped shell, open at either or both ends. The 
embryo then freed itself from the thin vitel- 
line membrane and squeezed through the 
polar opening. 
Similar observations have been made by 
Ransom (1904), Sanders (1928), and Fielding 
(1927). 
Development in the intermediate host 
Eggs were obtained from gravid female 
worms and were fed to young laboratory- 
raised roach nymphs. One nymph was dis- 
sected 24 hours after feeding, and numerous 
embryonated and non-embryonated eggs 
were found in the crop. No eggs or egg shells 
were found in the feces of the nymphs ex- 
amined at this time. 
At 48 hours, several first-stage larvae were 
found free in the lumen of the crop and an- 
terior midgut, and many others were observed 
in the process of hatching. The empty shells 
were barrel-shaped, which suggested that they 
hatched by splitting off one or both polar 
caps, as previously described. Several of the 
larvae were rather firmly attached to cellular 
