yo NEW GTRODACTYLOID TRESIATODES FROM AUSTRALIAN PISHES, 



8. Subgenus b. Diplectanotrema, n.subgen. 

 [Syn. Dipleetamim (in part).] 

 A small woi-m, having the usual characteristics of Ancyrocephalus, but dif- 

 fering in the very remarkable disposition of the vitellaria, which are arranged 

 in the form of numerous separate yolk-giands along the whole of the length of 

 the body. Ovary and testis situated in anterior quarter of the animal. 



From the gills of the marine fish Teuthis hepatus and Anisotremus virginicus. 

 Known only from the United States. 



Type species, yl. {Diplectanotr.ema) pleurovitellum (MacCallum, 1916). 



9. Tetraonchus Diesing, 1858. —emend. J. & T. 



(Syn. Dactylogyrus G. R. Wagener, 1857 (in part); Monocoelium Q. Wegener, 

 1910.) 



TetraoncMnae in which the disc is broader than the body. Pour large hooks 

 articulating with a large ehitinous supporting apparatus (furcula) ; fourteen 

 minor hooks. Four eyes. Intestine not bifurcated; devoid of caeca. Testis in 

 middle of body. Vagina apparently absent. Fenis with accessory clasping ap- 

 paratus. 



Type species, T. monenteron Wagener, 1857, from the gills of Esox 

 luetics. The genus is known only from Europe (freshwater). The synonymy of 

 this genus has been discussed in connection with Ancyrocephalus. 



10. A M p H I B D E L L A Chatin, 1874. 



Relatively large T~etraonclvinae measuring about 4 to 6 mm. in length. Head 

 rather pointed. Disc fairly distinctly marked off from body. Twelve minor 

 hooks always (?) present. No eyes. Intestine bilobed, devoid of caeca, the 

 limbs not joining behind. Vagina apparently absent. YoLk system confined to 

 a region posterior to the transverse yolk-duct. Penis simple. 



Type species, A. torpedinis Chatin, 1874. From the gills of marine 

 fishes {Torpedo and allies). 



Not yet reported from Australia. 



Monticelli (1889, p. 116; 1890; 1903, p. 336) regards AmpJdbdella as a 

 synonym of Tetraonchus, i.e. of Ancyrocephalus. The pointed head, absence of 

 vagina, and the remarkable position of the yolk system are character's which 

 oppose this view. 



Known species, A. torpedinis Chatin, 1874 (Mediterranean) nee MacCallum, 

 1916; A. flavoUneata MacCallum, 1916 (Massachusetts). 



Amphibdella maccailumi, nom. nov. 

 {Syn. A. torpedinis MacCallum, 1916, nee Chatin.) 



A comparison of MaeCallum's figure of A. torpedinis with that given by 

 Parona and Perugia (1890) leads us to conclude that the Mediterranean and 

 American forms belong to different species and hence we have removed the 

 latter from Chatin's species and renamed it as above. 



Host, Tetranarche occidentalis (from Massachusetts). 



11. H A L I o T R E M A, n.gen. 



TetraoncMnae in which the disc is distinctly marked off from the body, and 

 is provided with four large hooks supported by ehitinous bars, as weU as with 



