564 A DESCRIPTION OF THE ENTOZOA COLLECTED BY DR WILLEY 



the above diagnosis appreciated the fact that this snake was discovered inside the 

 stomach of another called by the natives a Taluluka and kindly identified by 

 Mr Bouleuger as Nardoa boa F. Miill. In the British Museum catalogue this last- 

 named snake is recorded from the Duke of York Island and New Ireland; as Dr Willey's 

 specimen was taken inland near Blanche Bay, ^ew Britain, its range is slightly 

 extended. 



The Dipsadomorphus has suffered to some extent for the digestive action of the 

 Nai-doa. The flesh on the skull was beginning to disappear but the part which had 

 suffered most began about six inches behind the head and extended some six or 

 eight inches. Here the ventral body wall of the body was completely digested away, 

 leaving the ribs sticking out of the sides of the body like rows of tomb-stones. It 

 was within the cavity thus laid open that Dr Willey found the parasites which he 

 describes as " devouring " the swallowed snake. 



Which of these snakes is the host of Porocephalus tortus is an interesting subject 

 for speculation. Possibly both are. It is not so common to find mature Porocephali 

 in the body-cavity as in the lungs of snakes, but cases of the former habitat are 

 described. I know no case of the adults being found in the stomach of a host. It 

 would further seem improbable that parasites subsisting on the healthy, living body 

 of an animal would desert it to attach themselves to the tissues of another animal 

 which is not only dead but half-digested. On the whole the evidence points to the 

 Dipsadomorphus irregularis being the normal host, though the parasites could evidently 

 live well enough in the gastric juices of Nardoa boa. As a rule Linguatulids endeavour 

 to quit a dead host and it seems strange that they retained a hold on the swallowed 

 form so long. I should have expected them to attach themselves to the living host 

 as soon as the way became open. 



Curiously enough although a considerable portion of the anterior end of the 

 swallowed snake had actually been digested away there were no signs of corrosion at 

 all on the posterior two-thirds of its body. 



The measurements of the fresh specimens of Porocephalus tortus were a little 

 larger than those I recorded from spirit specimens. Dr Willey gives the length of 

 the largest as 30 mm., mine was 43 mm. He gives the length of the head as 6 mm. 

 or including the neck 7 mm., I gave it as 5 mm. He measures the width of the 

 head at b'b ram. and the width of the body, which he states is " quite round," at 

 4 mm. I made the latter measurement, taken from somewhat wrinkled specimens, 

 2'53 mm. Evidently the animals had shrunk in the .spirit. 



In my first description of P. tortus I was able to figure three stages, a young 

 form with some 25 rings and no twisting of the body, an intermediate form in which 

 the twisting had commenced but the rings were still visible just behind the neck, 

 and a mature form markedlv twisted ami without trace of rings. I am now able to 

 give a much better figure of the mature animal taken from a sketch of Dr Willey's 

 from life, and also to add a couple of figures of two stages younger than the ringed 

 specimen figured before (Figs. 35, 31 and 32, Plate LYL). 



The youngest of these is 2"2 mm. in length, and about 06 mm. in diameter at 

 the level of its greatest breadth. Behind it tapers to a tail (Fig. 31, Plate LVL). 

 Some viscera are visible through the semi-transparent skin. In this stage the ringing 



