Reference

D. Xu, Weibo Song, Ping Sun, X. Chen (2006): Morphology and infraciliature of the oligotrich ciliate Strombidium rapulum (Yagiu, 1933 Kahl, 1934 (Protozoa, Ciliophora, Oligotrichida) from the intestine of sea urchin Hemicentrotus pulcherrimus agassiz – Zootaxa – 1113: 33 - 40.