50 W. N. F. WOODLAND 



attachment. The ' posterior ' extremity of the body is similar 

 in form to the anterior, save that at the extreme end a well- 

 marked bay or semicircular inlet is situated, in the centre of 

 which is a contractile papilla which bears the three separate 

 openings of the ductus ejaculatorius, terminal excretory duct, 

 and vagina (PI. 3, figs. 1 1, 11, 12). In colour the parasites vary 

 from a creamy-white to orange-yellow (the usual colour being 

 a distinct yellow), and are almost always identical in tint with 

 the masses of fat attached to the mesentery of the fish they 

 infest. 



The above statements concerning the dimensions and shape 

 of the parasites are based on the appearance of the parasites 

 when the body-cavity of the fish is first opened. 8o long as 

 the parasites are not disturbed they exhibit no active move- 

 ments, save perhaps a to-and-fro motion of the protruded 

 ' proboscis ' which is only visible under the microscope (PI. 4, 

 fig. 15), but if a parasite be removed from the body-cavity 

 and placed on a glass slide the body almost immediately shrinks 

 to about one-half its former length and also becomes pinched 

 by two, three, four, or more deep transverse constrictions ^ 

 which usually travel down the body antero-posteriorly, new 

 constrictions appearing anteriorly as the old disappear 

 posteriorly (PI. 3, fig. 1, /, g, h) ; the ' proboscis ' also either 

 becomes extruded (PI. 4, fig. 15, a) and active in penetration 

 movements, or (more usually, especially when the animal is 

 placed in water) becomes tightly retracted and immobile 

 (PI. 4, fig. 15, h). 



Amphilina paragonopora is, as I have already stated, 

 usually found in the body-cavity of the fish. I have most 

 frequently found it on the mesentery, or on the peritoneum, 

 or on the surface of the liver. On some occasions I have 

 found specimens lying underneath the peritoneum, and once 

 a specimen, 40 mm. in length, was discovered lying imme- 

 diately dorsal to the gas bladder, in the dense connective 



^ Heiu has described similar contractions as occurring in A. foliacea, 

 but states that they are feeble (the worm is very broad) and move postero- 

 anteriorly, i.e. in the reverse direction to that described m the text {!). 



