PLATE III. 



The lettering is the same in all the figures. 



cu Cuticula. 

 ec Ectoderm. 

 en Entoderm. 



g Generative organs. 



h Mesenteries. 

 im Intermediary layer. 

 m Muscle-fibres. 



me Mesoglosa. 



nis' Upper circular muscle. 



ms* Lower circular muscle. 



Ov^. 



r Marginal spherules. 



sr Siphonoglyphe (oesophageal groove). 



t Tentacles. 



All statements given as to magnifying powers have reference to Zeiss's system. 



Fig. 1. Circular muscle of Stephanidium schuhii ; — la, in the region of an inter- 

 mesenterial chamber and of a marginal spherule ; 1 6, in the region of the origin of a 

 mesentery. 



Aulorchis paradoxa (figs. 2-6). 



Fig. 2. Transverse section through the oral disc. A, Oc. 1, somewhat diminished. 



Fig. 3. Parts of a transverse section through the circular muscle, showing the 

 connection of the endodermal and mesogloeal muscle-layers : 3a, with D, Oc. 1 ; 3&, 

 with E, Oc. 1 . 



Figs. 4, 5. Sections through the stomidia. a^, Oc. 1. 



Fig. 6. Transverse section through the mesoglcsal musculature of the oral disc. 

 D, Oc. 1. 



Fig. 7. Stephanidium schuhii; upper edge of the body -wall, x 60. 



