Oxyspimra mmsoni — Schwabe 
29 
TABLE 5 
Measurements of First-stage Larvae (All Measurements in Microns) 
measurements 
DAYS AFTER INFECTION 
3 
5 
8 
17 
18 
Length 
125 
174 
207 
249 
286 
Width (ant. end) 
7 
7 
7.5 
7 
Esophagus length 
57.1 
107 
93 
Anus to post. end. 
49.9 
46.4 
39.2 
32.2 
Width (max.) 
14.3 
17.8 
17.8 
32 
18 
aperture was often seen with a posterior cuti- 
cular fold partially covering it, and a few large 
rectal cells (apparently three in number) were 
well developed. 
A nerve ring was seen encircling the es- 
ophagus at approximately two-thirds of the 
distance from its anterior end. 
Neither an excretory pore nor an excretory 
cell was apparent in this stage. 
A minute genital primordium, approximate- 
ly 75 m from the posterior end, was visible on 
the ventral body wall in several living speci- 
mens. 
Second-stage larvae 
Rapid growth occurred during this stage 
of larval development. The length increased 
from 990 fj, in early second-stage larvae to 
6.62 mm. in the latter portion of the stage. 
The larvae were long and slender with taper- 
ing tails, on the end of which four small 
papillae were discernible in the later part of 
the stage. 
The cuticle was relatively thin and bore 
marked transverse striations. A provisional 
buccal capsule had begun to form, but no 
cephalic papillae were visible. 
The esophagus was long and slender and 
in the late second stage extended approxi- 
mately one-half the length of the body in 
some larvae. Two gland-like structures were 
apparent at its anterior end, and the esopha- 
geal-intestinal valve was well formed. 
The intestine was a well-defined, thin- 
walled tube, varying only slightly in diameter 
and extending from the esophagus to the 
rectum. The cellular structure of its wall was 
apparent. 
There were three large rectal cells and 
several smaller ones immediately anterior to 
the anus, which was located ventrally approx- 
imately 170-190 fx from the posterior end. 
TABLE 6 
Measurements of Second-stage Larvae 
measurements 
days after infection 
27 
33 
40 
40 
45 
Length 
999.6 
54 
67.8 
1.85* 
2.6* 
4.5* 
6.62* 
Width (ant. end) 
53.5 
89 
24 
38.5 
107.8 
62 
52 
Width (middle).' 
170 
172 
Width at anus 
92.4 
400 
77 
85 
Esophagus length 
357 
616 
749 
Esophagus width (post, end) 
43 
Anus to post, end 
53.5 
160 
170 
246 
250 
Excretory pore to ant. end 
178 
250 
360.5 
Nerve ring to ant. end. 
89 
160 
185.6 
Intestine width . . 
62 
112 
Genital primordia to post, end 
890 
*These measurements in millimeters; all others in microns. 
