NEW CESTODES FROM THE TASMANIAN DEVIL. G89 



The Genercdim organs of this tapeworm begin to be recog- 

 nisable very early in the body, only a segment or two behind the 

 head. But it is a long way back before the ovaries are ripe. As 

 in the vast majority of Cestoidea, the testes ripen earlier than the 

 ovaries. This being the case, the testes are recognisable earlier 

 as distinct bodies, and only cease to be so clear in the more pos- 

 terior segments, where the uterus is gorged with eggs. A remark- 

 able point of interest in the generative organs is the fact that the 

 duct leading to the exterior, or to be more exact the formative 

 mass of cells which will be both vagina and cirrus sac, is seen to 

 alternate in position in relation to the single water vascular tube 

 and the nerve-cord. In all segments the actual opening is on the 

 same side of the body, but the generative duct passes towards it 

 either between the water-tube and the nerve-cord or outside of 

 both ; in the latter case only to one side — there is no alternation 

 between a dorsal and a ventral position. We shall see, when the 

 cirrus sac and vagina come to be described later, that there is 

 also variation in the exact relationship in position between these 

 two. 



The ovaries are lai'ge and consist of two wings, which are 

 symmetrical or very nearly so, the middle jDoint between them 

 being the middle line of the body, where are situated the shell- 

 gland etc. The ovaries are posterior in the segment, and behind 

 them lie the vitelline glands. These latter are of much the same 

 shape as the ovaries, and in rather immature segments differ only 

 from them by their rather darker staining with htematoxylin. 

 They also form two wings symmetrical with their middle point, 

 and are in contact with the ovaries in front. The two glands are 

 composed of many lobes, which reach as far as the testes at the 

 sides ; altogether an ovary occupies fully half of the segment, and 

 rather more when it is fully mature. Immediately in front of it 

 are the sperm-duct and vagina. At the sides are to be found the 

 testes, v/hich are also dorsal to it. 



The vagina offers no very remarkable character. It has at first 

 a contracted lumen, which widens out for a consideiable space, 

 and then contracts again before it suddenly opens into the rather 

 pear-shaped receptaculum seminis. The course of the vagina is 

 quite straight between its two ends and oblique in direction. 

 The narrow part of the vagina which opens into the receptaculum 

 is of some length, but shorter than the wider part. The vagina 

 shows quite the same characters in the most mature proglottids. 

 The receptaculum seminis is full of spermatozoa, and very 

 frequently contained ova at its wider end, close to where the 

 oviduct opens into it. The receptaculum and the vagina lie 

 anteriorly in the segxnent in fi'ont of the ovary, but behind the 

 uterus. 



The uterus of this worm is persistent and found as a large 

 cavity extending right across the segment in the most mature 

 proglottids that I have examined. It begins as a small rounded 

 cavity lying in the front part of each segment. 



