168 TEANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



the others and non-motile, they are presumably tactile. 

 No rhabdites were to be observed in the skin although in 

 living specimens pressed on the slide a considerable 

 amount of viscid mucous matter was extruded from the 

 epidermis. I have found no trace of the epidermal glands 

 so characteristic of Graffilla tethydicola. 



There is an outer circular and an inner longitudinal 

 muscle layer. The pharynx passes off into a well marked 

 oesophagus (fig. 8). The oesophagus soon widens out 

 into the very extensive gut, which has histologically the 

 characters described by Bohmig. The extent of the lumen 

 of gut depends upon the amount of food recently absorbed 

 by the cells, and may be said to vary inversely as the 

 amount of granules and vacuoles in the gut cells them- 

 selves. The gut occupies the whole volume of the animal's 

 body posteriorly to the germ glands or testes, excepting 

 the small space left between it and the body wall, in 

 which the great yolk glands ramify. 



The genital opening is a very short distance behind the 

 mouth, approximately on a level with the posterior opening 

 of the pharynx, so that in a section it is possible to get 

 the eyes, the genital opening and the posterior end of the 

 pharynx in the same plane, as was actually the case in the 

 specimen from which fig. 7 is copied. The whole relations 

 of the genital organs are so exceedingly variable according 

 to the age of the particular specimen examined that they 

 will require separate descriptions, just as if the worm was 

 of separate sexes. 



This Graffilla presents one of the most extreme cases of 

 successive hermaphroditism with which I am acquainted 

 among the Turbellaria, specimens which present traces 

 of both male and female organs being very unusual. In 

 specimens measuring 1 — 1*8 mm. the male organs are 

 generally predominant, the most conspicuous organ is the 



