One of the distinctive features of Echinostoma is the head collar of spines which surrounds the mouth. A small oral sucker is visible at the anterior end, with a short esophagus leading to a prominent pharynx. Surrounding the mouth, the body is slightly inflated giving the appearance of a collar. Two clusters of 4 spines are particularly evident because they are viewed end-on and appear dark. If you look carefully, however, you can see the profiles of many of the more than 30 other spines that are present. These spines aid in attachment to the intestine of the host.
To the bottom of the photo is the large acetabulum. The walls are muscular and there is a cavity in the middle. The acetabulum also aids in attachment. The two intestinal ceca can be seen curving around the anterior margin of the acetabulum. Just lateral to the acetabulum is the ellipsoid cirrus sac, and the single black egg seen on the margin of the cirrus sac indicates that the terminal portion of the uterus passes there as well. On the lower margin of the worm, you can see some evidence of the small spines which cover the body, a further aid to attachment.