]^Q Art. 3. — T. Kaburaki : 



efferent ducts, which open here and there in scattered distribution 

 over the external surface of the pharynx. Similarly the ducts of 

 the eosinophil glands, formmg a large bundle, proceed nearly 

 parallel to the above with some distance betw^een to open at the 

 tip of the pharynx. Both tlie bundles of the ducts just mention- 

 ed are separated from each other by a zone of coiinective tissue 

 traversed by plexus forming nerves. 



The nerve plexus is much more conspicuous in the posterior 

 half of the pharynx than in the anterior and for the most consists 

 of several nerves connecting almost perpendicularly with one 

 another. The longitudinal nerves run nearly parallel to the 

 external surface of the pharynx. In iSt. trlgonocephala there exists 

 a strongly developed nerve ring nearly between the middle and 

 the posterior thirds of the pharynx, much as in Pr. lobata. In 

 Pr. lactea three fairly well developed nerves are seen, which 

 probably represent the rings, but in Ed. limuU I have failed to 

 recognise a similar ring. 



Besides, this zone is traversed by numerous radial muscular 

 fibres which run from the inner epithelium to the outer, but 

 never occur in any definite bundle. Between these radial fibres 

 there are a few nuclei wliich are exactly similar in appearance to 

 those of the general parenchyma. Only in sections of PJcl. limiili 

 I have also been able to find out a few loops of excretory canals 

 which were already demonstrated by some authors in the pharynx 

 of any other forms. 



lîiner Zone. — In structural respects this zone is apparently 

 analogous to the outer. The lining epithelium of the pharynx 

 lumen is continuous with the external. In both Pr. lactea and 

 St. trigo7iocephala the nuclei are displaced at about anterior one- 

 third in the muscular layer of circular fibres immediately beneath 

 the epithelium, while in Ect. I'lmuli they are altogether absent in 

 the whole internal epithelium. This muscular layer is developed 

 to a considerable extent near the middle of the pharynx and is 

 composed of numerous rows of fibres which are much more power- 

 ful in both Pr. lactea and Ect. limuli than in St. trlgonocephala. 

 Directly below this layer there exist longitudinal fibres in two or 



