TREMATODES OF THE NORTHUMBERLAND COAST 44 1 



like a comma. (The drawing shows a straightened prepara- 

 tion.) The length varies from 4 to 8 mm. All the measure- 

 ments here given are taken from a specimen 4*5 mm. in length. 

 The body is broadly rounded at the anterior end and tapers 

 to a point posteriorly. The greatest breadth is in the region 

 of the ventral sucker, where it measures o*6 mm. The front 

 end is slightly marked off from the rest of the body by a neck 

 which is situated about o'i6 mm. from the anterior end. The 

 body is flattened dorso-ventrally, particularly in the region 

 between the two suckers, where it is peculiarly concave 

 ventrally. 



The suckers are both strongly muscular and are circular, 

 with circular apertures. The oral sucker is much the smaller, 

 being only o"i2 mm. in diameter, with an aperture of o-o8 mm., 

 and is situated at the extreme anterior end. The ventral 

 sucker is large, measuring 0-40 mm. across. It occurs at 

 about the anterior fifth of the body. 



The worm is very tough, with a thick cuticle, armed with 

 sharply pointed spines, which gradually broaden as they 

 reach the centre of the body, and become more leaf-shaped. 

 The spines begin a short way below the neck, running all 

 round in rows, and arranged in quincunx order so as to give 

 the appearance of oblique striation (see plate xi., fig. i). Each 

 spine measures about o-oi mm. in length. Posterior to the 

 ventral sucker they thin out and are scattered more irregularly, 

 soon disappearing except at the sides, where they become 

 farther apart until the distance between the spines is twice as 

 great as in the fore part of the body. At the last seventh of 

 the body they disappear altogether. The spines originate on 

 the inner surface of the cuticle, and are arranged obliquely 

 with their apices directed backwards ; only the points reach 

 the surface. As they thin out posteriorly they are entirely 

 within the cuticle. 



The head is completely surrounded by a crown of two rows 

 of blunt spines measuring about o-oo8 mm. in length and 

 closely set together. The exact number was not ascertained, 



