| Hydrozoa (Hydrozoans)
Hydrozoa (hydrozoans) are a taxonomic class of very small, predatory animals which can be solitary or colonial and which mostly live in saltwater. A few genera within this class live in freshwater. Hydrozoans are related to jellyfish and corals and belong to the phylum Cnidaria.
See: http://en.wikipedia.org/wiki/Hydrozoa

A hydrozoan anatomy
Source: http://animaldiversity.ummz.umich.edu/site/resources/Grzimek_inverts/Hydrozoa/v01_id118_con_hydanat.jpg/view.html | Actinaraea granulata | | | | HF2516 | | Complexastraeopsis portlandica (Alloiteau, 1960) | | | | HF2523 | | Complexastraeopsis portlandica (Alloiteau, 1960) | | | | HF2513 | | Complexastraeopsis portlandica (Alloiteau, 1960) | | | | HF2514 | | Complexastraeopsis portlandica (Alloiteau, 1960) | | | | HF2519 | | Complexastraeopsis portlandica (Alloiteau, 1960) | | | | HF2507 | | Hydrozoa Owen, 1843 | | | | HF1271 | | Hydrozoa Owen, 1843 | | | | HF2104 | | Hydrozoa Owen, 1843 | | | | HFF2440 | | Hydrozoa Owen, 1843 | | | | HF2428 | | Hydrozoa Owen, 1843 | | | | HF2423 | | Hydrozoa Owen, 1843 | | | | HF2431 | | Hydrozoa Owen, 1843 | | | | HF2427 | | Hydrozoa Owen, 1843 | | | | HF2289 | | Hydrozoa Owen, 1843 | | | | HF2287 | | Hydrozoa Owen, 1843 | | | | HF2436 | | Hydrozoa Owen, 1843 | | | | HF2430 | | Hydrozoa Owen, 1843 | | | | HF2426 | | Hydrozoa Owen, 1843 | | | | HF2291 | | Hydrozoa Owen, 1843 | | | | HF2421 |
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