The Sessile Jellyfish is found in the eastern Pacific from British Columbia south to Baja California (Mexico) (Sealifebase 2011
). It is a sessile species of jelly found at depths of 2-15 m (Sealifebase 2011).
Sealifebase provides the following description of the species: "Goblet-shaped, to 4 cm total length. Calyx as long as wide, clearly demarcated from stalk, with scattered nematocyst wart. Stalk narrow; circular to quadrangular in cross-section; highly contractile, from 1/2 to 3 to 4 times calyx length; four chambered throughout. Arms short, tending to occur as four interradial pain. Secondary tentacles 15 to 30 per arm, short, capitate, outermost ones with enlarged adaxial glandular pads. Primary tentacles (anchors) eight, similar to abaxial secondary tentacles but smaller; each with a small, dark pigment spot near margin. Mouth quadrate with frilled lips. Coronal muscle well developed, entire, at subumbrellar margin. Radial subumbrellar muscles eight, in adradii, extending to arm tips. Subumbrellar nematocyst vesicles along margin, most numerous in perradii where they cover most of gonad surface. Gonads eight, in four perradial pairs. Each pair with obliquely oriented folds. Color of subumbrella, calyx, and stalk variable, ranging from tan to magenta. Subumbrellar nematocyst clusters vivid white. Gonads cream to tan with narrow, dark brown pigment band extending radially aver subumbrellar surface."