850 , ON A NEW ASEXUAL TAPEWORM. 



Female organs consist of a layer of gonadial tissue lying in the 

 medulla at its junction with the cortical layer from which ova are 

 shed into the body, which they permeate even to the outer layers of 

 the cortex. There is no trace of segmentally arranged gonads or of 

 a uterus, nor are the eggs surrounded by any kind of " capsule." 

 There is no vagina or female passage of any kind ; the vitelline 

 glands are totally absent. The ripe eggs are surrounded by a 

 thick hyaline shell and none were observed to be dividing and 

 no embryos were discovered in them. Thus it is possible that 

 fertilisation occurs outside of the body. 



These characteristics do not entirely fall in with those of any 

 other family of tapeworms. They obviously point to an affinity 

 with the Acoleidse, but do not definitely necessitate the inclusion 

 of this remarkable worm within that family. 



§ Anatomical Summary. 



It may be convenient to extract from the foregoing account 

 of this new tapeworm the more remarkable anatomical facts 

 which I have been able to make out. 



(1) The absence of a marked scolexin the Cysticercusoi a tape- 



worm which cannot be placed among the Bothriocephalids 

 and of which therefore it would be expected that the scolex 

 would be very prominent. And correlated with this the 

 necessary assumption that, as in Bothriocephalids, the 

 scolex only develops ^ari^assit with the growth in maturity 

 of the worm. 



(2) The enormous size of the strobila as compared with the 



bladder — a rare condition among the Tetracotylea, but 

 paralleled in Cysticercus fasciolaris. 



(3) The very thick layer of muscle surrounding the dorsal 



vessel of the excretory system and the bifurcation of the 

 transverse vessels round the dorsal vessel to open into the 

 ventral water vascular tube. 



(4) The total absence of generative ducts or (presuming that 



the species is dioecious) of the female tubes, which is, so 

 far as I am aware, a unique anatomical character. 



(5) The total absence of a uterus or of any trace thereof. 



(6) The difi'use and non-metameric character of the ovaries, 



which are not sharply difl:erentiated into relatively small 

 bodies of a definite shape. 



(7) The enormous quantity of eggs produced and their exist- 



ence in quite anterior as well as posterior segments ; the 

 eggs are, moreover, found quite as abundantly in the 

 cortical layer as in the medulla. The conditions observable 

 in this part of the generative system are simply an 

 exaggeration of what is to be met with in other genera, 

 where the eggs come to be ultimately scattered through 

 the medullary parenchyma. 



