TREMATODES OF AUSTRALIAN BIRDS. 243 



The ovary, which lies in the middle line on a level immedi- 

 ately in front of the anterior testis, is oval in shape and 

 0*388 x 0*291 mm. in size. A large " shell-gland" lies 

 behind and to one side of the ovary. The yolk glands are 

 confined to the field outside the intestinal limbs. Anteriorly 

 they extend to the base of the pharynx and posteriorly the 

 two lateral fields become continuous with one another 

 behind the posterior commissural loop of the intestine. 

 They are composed of small oval follicles about 0*08 x 

 0*053 mm. The uterus is very voluminous and is arranged 

 in numerous transverse loops, many of which stretch right 

 across the body, whilst others only reach from the middle 

 iine to the lateral edge. These loops are not directly trans- 

 verse, but have the backward inclination which seems to 

 be characteristic of the genus, the angle of inclination 

 becoming more marked as we proceed backwards, till at the 

 posterior end the last couple of loops on each side proceed 

 almost directly backwards on either side of the testes, 

 almost reaching the posterior end of the body. The proximal 

 portion is dilated to form a receptaculum seminis uterinum 

 and is filled with sperms. The eggs are very thin-shelled, 

 elliptical, and show an increase in size as one follows the 

 uterus towards the anterior end. The eggs in the end near 

 the ovary measure 0*187 x 0*107 mm.; in the distal part, 

 however, 0*241 x 0*107 mm. Bach of the eggs contains a 

 miracidium with a conjoined pair of dark pigmented eye- 

 spots. 



This species is very similar in structure to H. similis, 

 Stossich, parasitic in the abdominal cavity of Himantopus 

 atropterus, and to H. consimilis, Nicoll, parasitic in the 

 thoracic cavity of the Spur-winged Plover Lobivanellus 

 lobatus. Besides the differences in host and a number of 

 minor structural differences, such as the extension and the 

 position of the yolk-glands, it differs from the two named 

 in having considerably larger eggs, which when mature 



