214 ON THE OOCURRENCE OF '' WORM-NODULES IN CATTLE 



variation in the mature parasites. The following summary 

 is taken mainly from the papers just referred to : — 



The female is very long, but its exact length is unknown, 

 owing to the impossibility of extracting it entire. By 

 adding the lengths of all the fragments collected from a 

 single nodule, apparently containing only one parasite, 

 we (1910, c) found measurement to be 97 cm., while Gilruth 

 and Sweet found it to vary from 52 to 140 cms. The cuti- 

 cular ornamentation is in the form of series of spirally 

 arranged ridges, each ridge being made up of a series of 

 undulations. The anterior end is bluntly rounded, bearing 

 a tiny papilla on each of the three small lips w^hich surround 

 the mouth. The diameter in the anterior part of the worm 

 is from '08 to '16 mm., and throughout the greater part of 

 the body is from -37 to -5 mm. The vulva varies in its 

 position, being situated between '46 and 1-23 mm. from 

 the anterior extremity. The nerve-ring lies at from -142 

 to .188 mm., and the excretory pore at from -36 to -38 mm. 

 from the head end. The anus is located at about -£0 mm. 

 from the posterior extremity. 



The male is a very thin and relatively short worm 

 with much less pronounced cuticular ornamentation. It 

 is scarcely half the width of the female and its length varies 

 between 3-75 and 5*3 cm. (Leiper ; Gilruth and Sweet.) 

 It is thus approximately only about one- twentieth of the 

 length of its partner. The nerve-ring is situated at from 

 •17 to '2 mm., and the excretory pore at -25 mm. from the 

 anterior end. The cloaca lies at a distance of from -048 

 to '072 mm. from the posterior extremity.* The two 

 spicules are unequal. The longer is from -14 to -197 mm., 

 and is a curved rod with a twisted stem and a pointed 

 distal termination. The smaller spicule is swollen character- 

 istically at the outer end. Its length varies from -08 to 

 •094 mm. There are six, probably seven, pairs of pipallse 

 on the tail end of the male. There is a peri-anal group, 

 consisting of four pair, and a caudal group of two pair. 

 At the extreme end there is a pair of minute pro- 

 jections, which probably represents the seventh pair. 



♦ In our paper (1910, c, p. 94) the distance in one case is given as 

 •072, and in another '65 mm. The latter is a misprint for '065 mm. In 

 our preliminary report (1910, a), the length of the smaller spicule was given 

 .as ^047, instead of '082 mm., and some of the papillae were overlooked. 



