jength. 

 mm. 



Maximum 



breadth. 



mm. 



4.03 



0.98 



4.53 



1.15 



4.80 



1.34 



4.36 



1.39 



5.16 



1.33 



5.82 



1.53 



6.46 



1.46 



7.82 



1.60 



XII, B, 4 Hilario and Wharton: Echinostoma ilocanum 207 



Table I. — Dimensions of 8 worms. 



No. 1 

 No. 2 

 No. 3 

 No. 4 

 No. 5 

 No, 6 

 No. 7 

 No. 8 



The greatest width of the body is at the level of the ventral 

 sucker, from vi^hich point the body tapers gradually to the 

 rounded posterior end. In front of the sucker is the head 

 region, which is generally bent dorsally at the level of the genital 

 pores; there is often a distinct constriction at this point. The 

 shape and length of the head region vary considerably in dif- 

 ferent specimens due to the difference in the state of contraction 

 of the worms. At the ventral sucker the body is almost round 

 in cross section, but it becomes flattened rapidly toward each 

 extremity. 



Color. — There is very little pigment in the body wall. The 

 fresh specimens were a transparent gray, and the testes, ovary, 

 and uterine coils could be seen distinctly through the walls. 



Cuticular spines. — Garrison says "the cuticle is smooth and 

 without spines." Odhner describes a well-developed armor of 

 scalelike spines which he says covers the anterior part of the 

 body and is perceptibly developed on the margins of the body 

 as far back as the border of the posterior testicle. We find in 

 our specimens a very remarkable variation in regard to this 

 feature of the body. In a few specimens the anterior part of 

 the body was fairly well covered with very small spines, but in a 

 majority of cases these spines are entirely lacking or are found 

 only in irregular patches along the margins of the body. They 

 are very unstable, and the least handling causes them to be lost. 

 The cuticle of two of our best preserved specimens is smooth and 

 shows no indications, even under a magnification of 400 diam- 

 eters, of ever having borne spines at any time. It may be that 

 the spines are developed and lost very early in the life of some 

 worms, or some may fail entirely to develop spines at any time. 

 When present they are so small that it is impossible to see how 

 they could be of any use to the worms. 



07'al spines. — Another variable feature of the anatomy is the 

 presence or absence of the wreath of oral spines around the 



