44 



Fig. 25. Longitudinal section of the lower portion of the 



oesophagus, x 320. 

 Fig. 26. Section of the ectoderm of the dorsal face of an 



arm. x 400. 

 Fig. 27 Portion of a longitudinal section of the anal 



funnel, x 320. 

 Fig. 28. The central portion of fig. 24. x 12. 



Plate III. 



Fig. 29. Transverse section of an arm. x 40. 



Fig. 30. A pinnular tentacle, in optical section. x 300. 



Fig. 31. Transverse section of pinnular tentacle, x 300. 



Fig. 32. An oral pinnule, x 12. 



Fig. 33. An ordinary pinnule, with ovary containing 



nearly ripe eggs. x 25. 

 Fig. 34. Distal end of a pinnule from the distal end of 



an arm. x 177. 

 Fig. 35. Fibres of extensor ligaments, x 400. 

 Fig. 36. Fibres of flexor muscle, x 400. 

 Fig. 37. Portion of longitudinal section of a pinnule, 



showing three ciliated pits. x 320. 

 Fig. 38. A cirrus, x 14. 



Fig. 39. Transverse section of brachial nerve cord, x 180. 

 Fig. 40. a & h. Vertical sections of two sacculi, showing 



stages in the formation of the masses of 



granules, x 320. 



Plate IV. 



Fig. 41. Ventral portion of a transverse section of an 



arm. x 110. 

 Fig. 42. Transverse section of ambulacral epithelium 



and the sub-epithelial nerve band, x 650. 



