42 



T.G. PILLAI AND HA. TEN HOVE 



Plate 2 Scanning electron micrographs of chaetae. A-D, Spiraserpula massiliensis (Zibrowius, 1968): A, bayonet chaetae. B, thoracic uncini. 

 C, anterior abdominal uncini. D, flat trumpet-shaped abdominal chaetae. E & F, 5. singularis sp. nov.: E, bayonet chaetae. F, abdominal 

 uncini. 



and they have been taken into consideration in the following 

 diagnosis: 



Tube with internal structures, usually towards its earlier 

 formed, coiled, posterior portions. They consist of internal 

 longitudinal ridges which vary in form and complexity in the 

 different species; they may be dorsal, along the convex inner 



wall of the tube, and/or ventral, along the opposite side. They 

 may be laminar, serrated or unserrated, or have other forms, 

 and accessory lateral ridges or other structures may also be 

 present. An umbilicus and peristomes may be present. There 

 is usually an external granular overlay which bonds together 

 coils of individual tubes, or those of other tubes to form 



