F. H. Stewart 
195 
Measurements of larvae of Ascaris marginata from the- liver of the 
mouse. The specimens were killed by heat in salt solution. Larva 
20 hours after infection. Total length, 0-38 mm.; oesophagus length, 
0-122 mm.; relation of length of oesophagus to total length, 1 to 3-11; 
maximum breadth, 0-017 mm. The length and breadth are practically 
the same as in the embryo, the oesophagus has shortened markedly. 
Larva on the third day after infection. Total length 0-42 mm.; 
oesophagus length, 0-130 mm.; length of oesophagus to total length. 
1 to 3-23. 
EXPLANATION OF PLATE IV. 
Fig. 1 . Ascaris suilla, larva from the caecum of the mouse, 12th day after infection, 
x 80. 
Fig. 2. Anterior portion of larva from the small intestine of the mouse, 10th day. x 800. 
Fig. 3. Anterior portion of larva from the faeces of the mouse, 11th day. x 800, 
Fig. 4. Excretory gland and duct of larva from the large intestine of the mouse, 11th 
day. Seen from a point on the prolongation of the radius midway between the 
dorsal and left lateral radii. x 1360. 
Fig. 5. The rudimentary gonad in a larva from the bronchi of the mouse, 9th day, 
x 1360. 
Fig. 6. Transverse section through a larva from the caecum of the mouse, 11th day. 
level of the excretory gland. x 1360. 
Fig. 7. Transverse section of a larva from the faeces of the mouse, 11th day, level ol 
anterior end of intestine. x 1360. 
Fig. 8. Transverse section of a larva from the caecum of the mouse, 11th day, im¬ 
mediately in front of the anus. x 1360. 
Fig. 9. Transverse section of a larva from the trachea of the mouse, 9th day, level oi 
the nerve-ring. x 1360. 
Fig. 10. Transverse section of the same larva, level of the excretory gland. x 1360. 
Fig. 11. Ascaris suilla, larva from the faeces of the mouse 10th to 11th day after infection 
Outline of the tail from the left side. x 689. 
KEY TO LETTERING OF ILLUSTRATIONS. 
a.c. anal canal; an. anus; d.l. dorsal line; e.ap. excretory aperture; e.c. excretory 
cell; e.d. excretory duct; int. intestine; 1.1. lateral line; l.l.l. left lateral line; l.m. 
lateral membrane; m. muscle cell; m.f. muscle field; n.e.c. nucleus of excretory cell; 
nl.e.c. nucleolus of excretory cell; n.r. nerve ring; oes. oesophagus; r.l.l. right lateral 
line. 
