Machaeridians, enigmatic Palaeozoic metazoans have a dorsal scleritome comp
osed of two or four longitudinal series of calcitic sclerites. Though rarel
y found complete, articulated specimens are an important source of informat
ion concerning form and function of the machaeridian scleritome. Here seven
articulated specimens from the Silurian of Gotland are described and refer
red to five species of lepid-ocoleid machaeridians. The specimens show sign
s of a terminal growth pattern (crowding of rugae near the accreting margin
), extreme dorsoventral elongation of sclerites, reflected by varying densi
ties of rugae. Narrow dorsal depressions which may limit the amount of scle
rite rotation, and possibly affecting the opening process of the scleritome
.