ILLUSTRATIONS 



Plate I, fig. 3, and Plate IV, figs. 1 and 2, are reproductions of camera-lucida drawings by 

 Teodosio S. Espinosa, the remaining figures are reproductions of photomicrographs by Charles 

 Martin. Plate I, fig. 2, and Plate II, fig. 2, are from stained preparations, the others from 

 unstained preparations killed in 70 per cent alcohol and mounted in glycerine. 



Plate I 



Fig. 1. Ovum of CEsophagostomimi apiostomum. x 350. 



2. Young rhabditiform larva, x 84. 



3. Young rhabditiform larva at higher magnification, showing the 



filiform tail, intestinal tract, and anlarge of reproductive organs. 

 X 390. 



Plate II 



Fig. 1. Cephalic end of young rhabditiform larva, showing shape of cesoph- 

 ag-us. X 350. 



2. Body of young rhabditiform larva, showing undulating course of 



intestinal tract. X 350. 



3. Young rhabditiform larva, showing posterior end of intestinal tract 



and anus. x 350. 



Plate III 



Fig. 1. Mature larva inclosed in skin of last molt, x 84. 



2. Cephalic end of mature larva inclosed in skin of last molt, x 350. 



3. Posterior part of body of mature larva inclosed in skin of last 



molt X 350. 



Plate IV 



Fig. 1. Cephalic end of mature larva, showing strongyliform oesophagus. 

 X 390. 

 2. Caudal end of mature larva. Note the long filiform tail of old 

 larval skin, x 390. 



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