papillosus of sheep and goats are 40 to 60 microns long by 20 to 25 
microns wide. The rhabditiform larvae and the filariform larvae are 
similar in a general way to those of S. stercoralis, figured in the 
paper on eggs and larvae of swine parasites. 
As previously noted, the eggs of the lung-worms belonging to the 
family Metastrongylidae hatch in the lungs and the larvae ascend the 
trachea and are usually swallowed, passing out in the manure. The 
larvae of the common lungworm of cattle, Dictyocaulus viviparus, are 
280 microns long by 25 microns wide when first hatched; these larvae 
have a button-like head and a rather blunt tail. The larvae of the 
common sheep lungworm, D. filaria, are somewhat similar. The larvae 
of the hair lung-worm of sheep, Synthetocaulus rufescens, are 300 to 
400 microns long by 16 to 18 microns wide and have a tail prolonged 
by an undulate appendix. The larvae of S. capillaris (Fig. 39) are 
similar and are 230 to 300 microns long by 20 microns wide. 
42 
