SCANNING ELECTRON MICROSCOPICAL OBSERVATIONS OF THE PROBOSCIDEAL PAPILLAE OF GLYCINDE ARMIGERA (ANNELIDA: POLYCHAETA)

Scanning electron microscopical observations on the papillae of the proboscideal organs of Glycinde armigera present the first clear picture of the morphology of these complex structures and reveal some misconceptions based on earlier light-microscope studies. The number of papillae in area III showed a greater range (2 to 8 rows) than previously reported, and only one row of papillae was present in area IV. Tufts of cilia were recessed within subapical, cuplike depressions on the papillae of all areas. The proboscideal papillae of G. armigera appear to provide traction for burrowing and may participate in food gathering. Additional key words: Goniadidae The large eversible pharynx, or proboscis, of goniadid polychaetes is one of their most impressive features. In Glycinde armigera Moore 1911 and other goniadids, the external surface of the everted proboscis is covered by structures variously called proboscideal organs (Hartman 1950; Hubendick 1952; Pettibone 1963; Day 1973; Gardiner 1976; Gilbert 1984) or proboscideal papillae (Pettibone 1963; Day 1973). The term "papilla" will be used here to refer to that part of the organ that projects from the surface of the proboscis. Hartman (1950) described the external morphology of the sclerotized papillae of G. armigera and grouped them into 5 areas (I to V, dorsal to ventral) for easy reference; the papillae of area II, constant in number and position, were designated with numbers from II-1 (dorsal) to 11-6 (lateral) (Figs. 1-4). The form of the papillae is of taxonomic importance as a diagnostic character. However, past descriptions of goniadid proboscideal papillae based upon light microscopy (Hartman 1950; Hubendick 1952) have been misleading or inadequate. The present study is the first survey of the structure of the proboscideal papillae of G. armigera using scanning electron microscopy (SEM). The observations reported here clarify earlier misconceptions of the basic morphology of the papillae and may also serve as a basis for comparison with the papillae of a To whom correspondence should be addressed. other goniadids and those of the closely related gly-