PLATE II. 



The lettering is the same in all the figures. 



cu CutiL'ula. 

 ec Ectoderm. 

 en Endoderm. 



<7 Generative organs. 



h Me.senterics. 

 ill) Intermediary layer. 

 m Muscle-fibres. 



me Mesogla?a. 



ma^ Upper circular muscle. 



m.«' Lower circular muscle. 



Ova. 



r Marginal spherules. 



m- Siplionoglyphe (oesophageal groove). 



t Tentacles. 



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



Fig. 1. Portion of the circular muscle of Hormathia delicatula. D, Oc. 2, somewhat 

 diminished. 



Fig. 2. IlyantJwpsis longijilis ; musculature of the oral disc. ViS' Oc. 1. 



Fig. 3. Hormathia delicatula ; musculature of the oral disc. D, Oc. 2. 



Fig. 4. Circular muscle and marginal spherules oi Li2)onema mtiUiporum. A, Oc. 1. 



Fig. 5. Muscle-pennon of Halcampa herguelensis. A, Oc. 2. 



Fig. 6. Dysactis crassicornis ; transverse section through a tentacle, a', Oc. 2. 



Fig. 7. Portion of the tentacle represented in fig. 6, more strongl)^ magnified. 

 A, Oc. 1. 



Fig. 8. Phellia spini/era ; transverse section through the musculature of the oral 

 disc. E, Oc. 2. 



Fig. 9. The same. 



