[LABIA. 173 



to extricate the filaria, and consequently its length is not 

 accurately known. We have measured all the fragments 

 obtained by teasing out a nodule from which only one head 

 (a female) was obtained, and found that the total length 

 was 970 mm. Probably the male would be much shorter, 

 as is usual in the Filariidse. The greater part of the body 

 in both sexes is uniform in diameter; that of the female 

 being from 0'3.5 to 0'43 mm., whilst that of the male is 

 only about 0"15 mm. 



The whole of the cuticle, especially in the female, is 

 ornamented with a very regular series of ridges (fig. 2) 

 which travel round the body in a spiral fashion. There 

 are really two series of spirals as each ridge may be traced 

 to the next but one. This structure appears to be the 

 same as that figured by Railliet 1 as occurring in Filaria 

 (Spiroptera) reticulata, Dies. Each ridge is made up of a 

 series of projections and depressions. Throughout the 

 greater portion of the worm these ridges are very distinct, 

 but anteriorly in both the male and female, especially the 

 former, they become gradually less prominent and eventu- 

 ally indistinguishable. For instance, though very small 

 they may still be seen in the region of the vulva. The 

 following measurements taken from a female worm shew 

 the progressive divergence of the spirals. Just behind the 

 vulva they are very low and numerous, there being about 

 140 rings in 0*5 mm. This number decreases rapidly until 

 there are 15, then 14 and so on until the usual number is 

 from G to 8 in the same distance. In the case of the male 

 there are about 100 rings in 0"5 mm. The ridges here are 

 very small and closely set. The transverse striations 

 figured by Railliet have not been seen by us in F. f/ibsoni. 

 The cuticle, however, is very finely longitudinally striated. 



1 Railliet, Traite d. Zool. Agric. et Medicals, Edit 8, 1886, p. 539, 540; 

 and reproduced in Neumann's " Pat a • 2i I Edil Bngliafa Transla- 



tion) 1905, p. 552, fur. 328. 



