320 CEYLON PEARL OYSTER REPORT. 



Fig. 23. Panthalis melanonoius. Lateral processes of four successive segments after the 28th, showing 

 dorsal cirri with geniculate appendices, alternating with elytrophores and ovate processes ; 

 seen from above. 



24. Panthalis melanonoius. Superior ventral seta. 



25. ,, Penicillate seta. 



26. Aristate seta. 



,, 27. ,, Inferior ventral seta. 



,, 28. Panthalis nigromaculata. Anterior end. 



_,, 29. Head. 



30. Jaws. 



,,31. Third elytron. 



32. ,, Parapodium. 



,, 33. Psammolyce zeylanica. Two of the dorsal dermal papillae 



34. Head and portion of the anterior segments. 



PLATE II. 



Psammolyce zeylanica. Dorsal cirrus of third segment. Z. 3 a.* 



,, Compound seta from second segment. Z. 3 C. 



Shaft of compound seta from third segment. Z. 3 C. 



,, Seta from central fascicle of neuropodium. 



Inferior ventral seta. 



Appendices of bidentate seta?. 



Lower border of parapodium with ventral cirrus. 



An elytron. 



,, Seta from central fascicle of 16th foot with cusp on shaft. 



Psammolyce rinida. Seta from central fascicle of 16th foot with plain shaft. 



,, Dorsal cirrus of third segment. Z. 3 a.* 



,, An elytron. 



,, Compound seta from second segment. Z. 3 C. 



Sthenelais zeylanica. Parapodium: v.c, ventral cirrus with its associated stylodes; 1, 1, 1, 

 superior dorsal seta? (numerous, forming a dense tuft) ; 2, 2, inferior dorsal seta?, slender, 

 striated ; 3, superior ventral seta ; 4, seta of the central group ; 5, inferior ventral seta. 

 Sthenolepis japonica. Parapodium. 

 Tkalenessa digitata. Superior ventral seta ; the upper end of the shaft is faintly fringed. Z. 3 D. 



,, One of the digitate fimbria? of an elytron. 



,, Anterior end : e., first elytrophore ; p., palp ; x., semilunar process of the 



second foot arching over the prostomiuni. The porrect cirrophores carry no visible seta?. 



PLATE III. 



Thalenessa stylolepis. Head. 



,, Parapodium showing the ctenidium on the medial surface of the elytro- 



phore and the cirriform branchia below the elytron ; the marginal fimbria? of the latter are 

 concealed in this preparation. 

 Thalenessa stylolepis. Compound seta from the 60th segment. Z. 3 C. 

 ,, Marginal plumose fimbria of an elytron. Z. 3 A. 



