﻿PARAGONIMIASIS IN THE PHILIPPINES. 33 



longitudinal sections, it is observed that the spines at the extreme cephalic 

 extremity are smaller and that they become larger toward the equa- 

 torial portion and again slightly smaller at the caudal extremity. In 

 places, such as on the dorsum, these spines seem to extend above the sur- 

 face more than they do in other situations, whereas along the caudal por- 

 tion of the ventral surface their projection above the surface is hardly 

 noticeable in sections. The varying direction of these spines as they are 

 seen in sections from different worms would suggest that, during life, the 

 animals may have the power of moving them and, perhaps, of using them 

 in locomotion or in holding themselves in position for other purposes. 

 This hypothesis of motion is further born out by the unique arrangement 

 and setting of the spines in the skin. They rise from the inner surface of 

 this organ, penetrate it at fairly constant and parallel angles, and are 

 very closely held in place. Alternate layers arise from a slightly more 

 superficial layer of the skin, but these pass out, as do those from the deeper 

 tissues. 



Oral sucker: This is spherical or slightly oval in shape, the largest 

 diameter always being ventro-clorsal, it is terminal to subterminal, and in 

 the living parasite it may change from one to the other of these positions. 

 Measurements have only been possible- in preserved specimens, and here 

 acenrate work with a Zeiss photomicrographic apparatus gives 0.86 milli- 

 meter as an average of 10 specimens, the smallest being 0.63 and the 

 largest 0.97 millimeter. The sucker is composed of onter and inner, rather 

 definite, membranes which are connected by radiating fibers interspersed 

 with small, granular cells. The outer membrane apparently connects 

 directly with the parenchymatous muscle fibers of the parasite. The 

 lateral lips of the sucker are heavier than the ventral and dorsal ones. 



Ventral acetabulum : This is slightly larger than the oral sucker. The 

 average measurements in the parasites used in measuring the oral sucker 

 gave 0.92 millimeter, the smallest being 0.76 and the largest 1.31. It is 

 slightly oval or spherical in shape, and in structure it closely resembles 

 the oral sucker. It is situated in the cephalic half of the body, on the 

 ventral surface. At times its surface seems to be parallel with the ventral 

 surface of the parasite and again it appears to form quite an angle with 

 the latter. The distance of the acetabulum from the oral sucker is a 

 changing one during the life of the parasite; this is due to contractions 

 and protrusions of the cephalic portion of the worm. 



Pharynx: This is a constricted portion of the oro-cesophageal tube and 

 it does not differ in structure from the oesophagus. 



GEsophagns: This organ is short and finally divides into the two intes- 

 tinal caeca. Together with the pharynx, it arches somewhat clorsally from 

 the oral sucker to its bifurcation; in structure it resembles the oral 

 sucker. 



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