(1) Ten species of Tubificidae are recorded from Cape Cod Bay, as follows: Adelodrilus anisosetosus, Limnodriloides medioporous, Peloscolex apectinatus, P. benedeni, P. intermedius, P. nerthoides, Phallodrilus coeloprostatus, P. obscurus, P. parviatriatus and Tubifex longipenis. (2) Phallodrilus parviatriatus nov. sp. is characterized by small erect atria and simple-pointed posterior setae.