CESTODA. 3 



stained and fairly conspicuous. The yolk-glands are widely scattered through the 

 peripheral parenchyma. 



The uterus is not fully developed in our specimens, which must be rather immature. 

 It consists of few branches somewhat rosette-shaped. The ova are thin-shelled, and 

 measure 0-032 by 0-028 mm. 



DiBOTHRIOCEPHALUS SCOTTI. 



The second species of Dihothriocephalus found in the alimentary measured about 

 8cm. in length (fig. 3). One attained a length of 9cm., but the other three or four 

 specimens were shorter. The number of proglottides is some 150. The head is 

 rounded, not at all conical, but like the amber mouthpiece of a Turkish pipe (fig. 4). 

 The slit-like grooves are dorsal and ventral. The head measures 1mm. across, and 

 perhaps a little less from before backward. It is succeeded by a neck which, in 

 some specimens, is a little narrower than the head ; in others about as broad. The 

 proglottides soon begin to be evident, but I do not think one can say there is no neck. 

 In this respect this worm differs from D. Mans of Leptonyx monachus, Wagn., Phoca 

 barhata, MlilL, and P. annellata, Nilss., which, in some respects, it resembles. 



The proglottides are at first some five times as broad as they are long, but sooner 

 or later — and it depends upon the state of contraction of the worm when killed, how 

 soon or how late — the proglottides become square, with parallel sides, and they remain 

 square until the end. The posterior border is slightly thickened, and stands out at 

 right angles from the body. It practically does not, however, overlap the succeeding 

 proglottis. 



The reproductive organs consist of numerous testes lying scattered superficially 

 through the proglottides ; the ducts of these presumably unite, though they could not 

 be seen, and open into an exceeding muscular penis, which in most cases is protruded 

 from the proglottis. The penis is situated in the middle line close to the anterior edge 

 of the proglottis. It bears no hooks. Close behind it opens the vagina, which makes 

 a coiling course backwards to where the two short oviducts from the ovary meet 

 it. The ovaries are two, somewhat pear-shaped ; they lie each side, near the hinder 

 end of the proglottis behind the uterus, and are of fair size. A minute shell 

 gland is visible at the juncture of the oviducts. No tube entering the uterus 

 is visible. 



The uterus is roomy, it opens on the ventral surface in the middle line, and about 

 half-way along the proglottis. The opening is circular. Just within this opening the 

 uterus forms a spherical chamber, which contains a fair number of ova. From this 

 chamber two or three lateral branches diverge, and these may be cut twice in one plane, 

 but in no sense is the uterus rosette-shaped. ' ^ 



The ova measure on an average - 04mm. by - 03mm., but the shaj)e varies ; some 



