44.0 WILLIAM NICOLL. 
ventrally, towards the genital sinus. It has a length of -45 
mm., and a diameter of ‘04-09 mm., becoming narrow as it 
approaches the genital sinus. Its section is not circular, but 
triangular, and this is constant in every case, being appa- 
rently in correlation with the triangular shape of the ova. Its 
wall is thick (‘012 mm.) and muscular, comprising the usual 
two layers, and it is lined by a thick cuticular membrane. 
The ova are fairly numerous and measure ‘084 by *0436 
mm. The shell is light yellow and about ‘0035 mm. thick. 
The shape is characteristic. In longitudinal section they are 
somewhat oval, but truncate at the anterior end and with 
a pointed knob, due to a thickening of the shell, at the 
posterior end. The operculum is very flat. In transverse 
section, however, they are triangular, the triangle being 
equilateral. This peculiar shape of the ova was first noted, 
I believe, by Odhner’ in the case of Orthosplanchnus 
arcticus Odh., O. fraterculus Odh., Lecithodesmus 
goliath (v. Ben.), and Brachycladium oblongum (Brn.). 
In his diagnosis* of the sub-family Bracnyctapinm Odh. he 
regards it as a distinctive feature differentiating the sub- 
family, amongst other things, from the Fasciouinm. He 
thus considers it to be of universal occurrence in the sub- 
family, and in particular in the genus Brachycladium Lss. 
He refers * to Poirier’s * figures of the ova of Br. rochebruni 
and Br. delphini as indicating that the ova of the species 
probably display the same shape. I fail to see any evidence 
of this in Poirier’s figures, and he himself certainly makes no 
reference to the triangular shape of the ova in transverse 
section.” Odhner conveniently ignores Looss’s statement® that 
» © Die Trematoden des Arktischen Gebietes ” in ‘ Fauna Arctica,’ iv, 
p. 343. 
2 Tbid., p. 347. 3 Thid., p. 346. 
* <Trematodes nouveaux ou peu connus,” in ‘Bull. Soc. Philomatique, 
Paris,’ sér. 7, vol. x, pl. iv, figs. 3 and 5. 
* It is quite possible that Odhner only means to imply that the ova 
in Poirier’s two species resemble those of the other BRACHYCLADIINE 
in being thick shelled, with flat operculum and pointed posterior end, 
but his statement in the sub-family diagnosis renders this doubtful. 
° * Zeitsch. f. Wissen. Zool.,’ xli, p. 419. 
