| During their resting hours from sunset to sunrise, they gather in closely knit aggregations in caves, under ledges, or in other protected areas. |
| These lymphocytes are located in the nodules of the spleen, lymph nodes, and lymphatic aggregations of the ileum. |
| They are most commonly seen as solitary individuals, but on occasion they appear in sizable aggregations, frequently near floating kelp. |
| Many hydrozoan species perform large vertical diel migrations, which may bring individuals together in spawning aggregations. |
| Large aggregations of birds can be found behind fishing boats, feeding on offal. |
| Present plant communities are evidently ephemeral aggregations controlled by intersecting gradients of floral change. |
