DURING HIS SOJOURN IN THE WESTERN PACIFIC. 563 



Superficie esterna dello strato cuticolare stesso, e rientra nel sottogruppo da me stabilito 

 nella monografia sopra citata, caratterizzato dalla presenza di un uollare nero ben 

 spiccato. Questo gruppo comprende appunto le specie fino ad ora state deseritte delle 

 Indie Orientali come il G. fulgur Baird, il G. doriae Camerano, il G. horsti Camer., 

 il G. salvadorii Camer. 



" II Gordius willeyi si differenzia facilmente da queste specie per la forma dei 

 lobi deir estremita posteriore ; facilmente pure si distingue dal G. villoti Rosa, pei 

 caratteri della cuticola esterna e per ([uelli dei lobi posteriori." 



V. LINGUATULIDAE. 



I. POROCEPHALUS TORTUS Shipley. 



In an article entitled "An Attempt to Revise the Family Linguatulidae'" published 

 in 1898, I gave a short description of a new species of this family of parasites which 

 I named Porocephcdus tortus. The specimens of this animal had been sent home by 

 Dr Willey and the description was written before he had completely sorted the 

 valuable material he had accumulated in the far East. He has now found some more 

 specimens and two more stages in the development of the animal, and has further 

 given me some more details as to the host and the dimensions of the parasites when 

 in the fresh state. Before mentioning these, however, I insert the description of the 

 species made from spirit specimens, quoted from the above-mentioned article. 



" The young form is very distinctly ringed, the number of rings is about 2.5. 

 In the mature forms the development of the genital organs has so stretched the 

 skin that the rings have disappeared, at the same time the body has become curiously 

 twisted as is shown in the figure, and this characteristic feature has suggested the 

 specific name which I have given to this form. The cephalothorax which includes 

 the first 3 or 4 rings is well marked otf from the bod}'. The rings, as the body 

 stretches, disappear last from the region behind the well-marked neck. 



"The hooks are single, the inner pair slightly in advance of the outer. The mouth 

 almost oval, and a little posterior to the inner hooks, a chitinous half-cylinder runs 

 back from it along the posterior face of the oesophagus. 



" Length of mature female 40 mm. The longest specimen measured 3 mm. 

 more but the others were very constant in their length. The head measured 5 mm. 

 The width of the body which was very constant behind the neck, only slightly 

 tapering towards the tail is 2, .5-8 mm. The length of the immature female whose 

 rings are just disappearing is 35 mm., and the length of the young form with well- 

 marked rings is 10 mm., its breixdth about 1 mm. 



"Habitat. In the body of Dipsadomorphus irrerjularis, from New-Britain. Found 

 by Dr Willey." 



The parasites were taken from within the body of a snake — Dipsadomorphus 

 irregularis Merrem, the Malagea of the natives, but I had not at the time I wrote 



1 Arch, parasit. i. 1898, p. .52. 



w. V. 75 



