250 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



the ectoderm, and, should future investigations prove 

 such to be the case, the Nemerteans would present the 

 interesting feature of possessing an endoderm which pro- 

 bably does not contribute to the digestive juices, but is 

 only concerned with absorption. But in the absence of 

 decisive embryological data, and of the histological 

 appearance of the various parts of the lining of the 

 alimentary canal after injection of various substances, 

 nutritious or otherwise, the question must be left open. 



The oesophagus is constricted at its posterior end, and 

 behind this constriction starts the intestine, with its 

 lateral pouches, where the character of the lining of the 

 alimentary canal becomes entirely changed. The intes- 

 tinal cells are large, though long and narrow (PI. III., 

 fig. 2). Each contains a somewhat elongated nucleus near 

 its base, whilst between it and the ciliated surface are a 

 number of small round bodies which shew neither nucleus 

 nor any definite structure. These little bodies have been 

 considered to be stored food material absorbed in this 

 region, and in some Nemerteans several types have been 

 distinguished. 



The region of the regularly arranged intestinal diver- 

 ticula (PI. III., figs. 6, and 7, i.d.) continues 

 almost to the anus where the alimentary canal opens to 

 the exterior by a very short rectum. It is worthy 

 of note that traces of food are rarely found in 

 the digestive canal of a Nemertean. Yet various 

 anecdotes illustrating their voracity have been given, 

 among which may be mentioned an observation of 

 *Riches, who, writing about Micrura jjurpurea, states that 

 " A specimen of about 3 or 4 cm. was placed in a dish with 



* Riches, T. H. A list of the Nemertines of Plymouth Sound. Journ. 

 Marine Biol. Assoc. Vol. III. 



