In this picture, the biotic associations of the rock scallop can be seen to consist of several hydroid species. Abietinaria rigida is number 3. 
Ectopleura is numbers 1 and 5.
| Domain | Eukarya |
| Kingdom | Animalia |
| Phylum | Cnidaria |
| Class | Hydrozoa |
| Order | Leptothecata (=Leptomedusae) |
| Family | Sertulariidae |
| Genus | Abietinaria |
| Species | rigida, Nutting 1904 |
| Common Name: | ———– |
This file is provided as part of a collaborative effort by the students,volunteers,staff and faculty of Lester B. Pearson College. 2005.
see this link for other hydroids: https://www.racerocks.ca/tag/hydroid/