110 NEW GYEODACTYLOID TKEMATODES rEOM AUSTRALIAN FISHES, 



No trace of nervous or excretory systems could be seen. There ai'e two- 

 pairs of eyes immediately in front of the pharynx, situated just below the body 

 wall in the parenchyma. 



The testis is well developed, lying immediately behind the ovary, and in 

 some specimens appears to be distinctly lobed. The vas deferens, which runs 

 dorsaUy to the ovai-y and to the right of the uterus, becomes dilated into a 

 large vesicula seminalis and, after narrowing, appears to open directly into the 

 cirrus, no bulbus ejaculatorius being visible. Into the base of the cirrus there 

 opens a small prostate gland. The cirrus is a short incompletely-closed chitinous 

 tube, bent once upon itself and opening immediately anteriorly to the female 

 genital aperture. 



The ovary lies transversely in the middle of the body. The oviduct is a 

 very wide, non-collapsible tube opening a short distance behind the oesophagus. 

 The well developed shell-glands are ari-anged in two groups on either side of the 

 oviduct into which they open each by a long delicate duct. There is no vagina. 

 The vitelline system which is not very strongly developed, lies in close con- 

 nection with the intestine and discharges its yolk by means of two narrow 

 transverse yolk-ducts, situated immediately anterior to the ovary. 



The egg which is relatively large, measuring approximately .06 mm. in 

 length, was rarely pi'esent. It is somewhat oval in shape, and possesses a short 

 posterior spine. 



Found on the gills of Therapon undcolor Gunther, from the Burnett River,. 

 South Queensland. 



19. A c L E o T R E Ji A, n.gen. 



Lepidotremiinxe. Disc considerably broader than body, with four- large hooks 

 and a supporting chitin apparatus ; fourteen minor hooks. The sucker-like organs 

 consist of about fifteen rows of modified scales and are devoid of accessory hooks. 

 Greater part of body protected by short proclinate spiny papillae. Pour eyes 

 present. Ovary and testis in the vicinity of the middle of the body. Vagina 

 thin-waUed, bent upon itself anteriorly and opening in the midline. Penis rather 

 simple, but lodged in a highly developed cirrus-sac. Penis and vagina com- 

 municate with a remarkable chitinous cavity which opens on the ventral surface. 



From the gills of a marine fish of the genus Girella. 



Type species, J., girellae J. & T. 



AcLEOTREiiA GIRELLAE, u.sp. (Plate xiii., figs. 23-25; siv., figs. 26-30.) 



Length of adult worm averages about .7 mm., breadth of body about .16 

 mm., breadth of disc about .23 mm. 



This is a rather slender species with a disc considerably broader than the 

 body. There is much variation in shape according to the state of contraction or 

 elongation of the individuals; at times the extension of the posterior portion may 

 be remarkably gTcat, the worm in this condition having a totally different ap- 

 pearance from that usually seen. It is chiefly the region posterior to the ter- 

 mination of the intestine which undergoes this elongation. 



The disc is provided with fourteen minor hooks, arranged as in PI. xiii., fig. 

 25 and PI. xiv., fig. 27, as well as with four large hooks which are supported by, 

 and articulate with a chitinous basal armature. The latter consists of a power- 

 ful transverse chitin-bar, the ends of which articulate each with a second, proxi- 

 mally bifurcated chitin-bar, while the two hooks on either side come into relation 

 with the end of the bar. One of these hooks is rather slender and possesses 



