The family Koellikeriadae. 151 



head witliout any special musciilar reinforcement is convoluted and 

 rather bulbous in this part ; posteriorly it divides into two branches 

 which extend into two of tlie lobes and expand into plicated sacs 

 — the testes. Not all the lobes contain testicular material and in 

 the two which do the organ is evidently a continuous tubulär sac. 

 Spermatogenesis may be observed very clearly in all stages. 



No excretory System could be clearly traced although there are 

 many thin walled Spaces and canals which doubtless have this 

 function. Practically no musculature is found anywhere in the 

 body except in the walls of the Uterus. The whole mass is composed 

 of a soft watery parenchyma of large cells and large Spaces Con- 

 densed into a firmer sort of connective tissue in the central mass 

 where the lobules are held together. The skin is delicate and 

 unarmed but provided with the usual cuticular cells. 



It is most difficult of all to understand how the body acquired 

 this peculiar shape and indeed to learn precisely what the relation 

 of the parts is. 



It was stated that the outer surface looked smooth and relatively 

 white but that it readily cracked and feil apart revealing lobules. 

 In section it is seen that the outer covering is not continuous over 

 a smooth surface but that while it Covers several lobulations it dips 

 down between the main ones. Then, too, a quite similar cuticular 

 covering is found upon lesser lobulations which are hidden in the 

 main mass and upon the inner side of the various parts which go to make 

 up the main lobulations. It is as though there were many folds or lobules 

 which had fused in groups wherever they presented externally so 

 that wliile over tlieir outer surface, skin and parenchyma became 

 continuous the inner parts remained discrete each covered there 

 with skin so that a whole series of little crevices or caverns arose 

 between these lobules roofed over by the fused outer part. It is 

 into these crevices everywhere that the vascular film from the host 

 finds its way and brings nutriment and oxj'genation. 



But all the lobules seem to fuse together at the centre into a 

 sort of common core of denser tissue into which the vasa deferentia 

 and the uterus run to enter the neck. The mass which contains 

 the Shell gland and the connection of ovary, vitellarium and 

 Uterus lies in this central part and indirectly connected with the 

 central core. 



It will be seen from this necessarily imperfect description that 

 this worm diifers in several respects from those already described. 



