o48 A DESCRIPTION OF THE ENTOZOA COLLECTED BY DR WILLEY 



IV. PALAIA VARAXI, u. gen. et sp. 



The following account refers to a new genus of Tape-worm taken by Dr Willey 

 from the duodenum of a lizard, Varanus indicus. The length of the tape-worm 

 averaged, in the nine specimens w^hich Dr Willey obtained, about 15 — 20 mm. When 

 they reached me they presented the appearance roughly indicated in Fig. 16, Plate LV. 

 The Jiead bore an enlargement, a species of frilled or puckered turban which gave 

 the animal a very characteristic look and vividly recalled the figures given by E. Linton 

 of Thysanocephalum crispum Linton, from the Tiger-shark Galeocerdo macidatus^. For 

 some time, even after I had prepared and examined sections, I thought this turban 

 was part of the parasite. It appeared to have its origin on one side of the neck 

 and to grow forward and over the head. In section the tissue of this part showed 

 a certain resemblance to the tissue of the parasite — perhaps this was due to imperfect 

 preservation — and the turban showed no definite resemblance to the lining of the 

 alimentary canal of a Vertebrate. Neverthele.ss I gradually became con\-inced that the 

 turban was part of the host and not of the parasite. With great care it was possible 

 to dissect the head of the tape-worm out of the turban and the head showed no 

 trace of lesion either when viewed as a whole or when cut into sections. On opening 

 a specimen of Varanus indicus it was found that the lining of the duodenum was 

 produced into just such papillae as the turban showed, and in cutting sections of 

 these they were seen to histologically resemble the turban in the tape-worm. Finally 

 Dr Willey recollected that as the animals w^ere so deeply embedded in the tissues 

 of the duodenum of the Lizard that he could not remove them without breaking the 

 worm, he had in each case cut out a small portion of the intestinal wall to save the 

 tape-worm's head. 



I cannot find that the worm in question belongs to any described genus and I 

 therefore must propose a new one, the diagnosis of which will be found on p. 550. 

 The name I suggest Palaia is derived from the native word for the lizard which 

 harbours it, and the specific name varani indicates the genus of the host. 



Palaia varani has a rounded flattened head which bears no hooks (Fig. 17, 

 Plate LV.). It is provided with four deep but weak suckers which sink into the 

 neck as well as into the head. The worm retains its hold of the intestinal wall of 

 its host not by these suckers but by its rounded head being sunk into a pit, the 

 edges of the pit contract and encircle the narrow neck and the head cannot be pulled 

 out through this orifice mthout first slitting it, at any rate in preserved specimens. 



The head as is shown in Figure 17, Plate LV. is somewhat wrinkled, and the 

 wrinkling is even more marked on the neck. There nre a series of longitudinal 

 grooves which are very deep, these give the anterior part of the body a star-shaped 

 section (Fig. 18, Plate LV.). When the longitudinal -wrinkles reach back to the com- 

 mencing transverse grooves the body becomes divided up into a number of small 

 quadrilateral areas. The transverse grooves which divide the proglottides are also deep 

 and give in section a characteristic appearance. When the proglottides however are 



1 United States Commission of Fish and Fisheries. Part xvi. Report for 188B. Washington, 1892, p. 543. 



