The taxionomy of Silurian Chonetoidea from Gotland (Sweden) needs to be revised. The present paper is the first part of a redescription, concerning mainly the palaeoecology of the genus Protochonetes. An attempt is made to carry out statistical measurements of specimens of presumable fossil populations (thanatocoenoses). It is concluded that all specimens belong to one species only, viz. Protochonetes striatellus (Dalman 1828) and that P. ludlowiensis Muir-Wood 1962 is but a broader variety of this species. The possible life-position of the chonetids was dorsal valve upside. This statement is founded on statical considerations. The function of the spines is thought to be a statical one. The preferred environment of the chonetids was obviously the fore-reef and back-reef area where the populations settled in shallow waters on shell-layers which had come to rest. This is inferred from sediment-ological data.