Marianne Moore’s poem “A Jelly-Fish” (1909) explores the notion of vœrtices in many senses. It is an excellent demonstration of how jellyfish embody the concept, not only the literal vœrtex in the fluid dynamic sense, but also the vœrtices at play within the aesthetic qualities and behaviour of a jellyfish, as seen through Moore’s use of juxtaposition and paradox. The metre of the poem is also an excellent example of how vœrtices can manifest within interactions between two beings, and demonstrates the resulting interplay of attraction and repulsion between each entity. 

Through the juxtaposition of opposites, the work is an exploration of the vœrtical nature of a jellyfish’s aesthetic qualities and behaviour. The poem opens with a paradox; “Visible, invisible” (line 1). This tension between opposites immediately positions the poem as vœrtical by drawing attention to the wavering clarity of a jellyfish underwater, with the jellyfish balanced at the point of conflict between being accessible or inaccessible to the human eye. Moore’s use of the word “fluctuating” (line 2) draws further attention to this balanced conflict within a jellyfish’s aesthetic qualities, both within this struggle between visibility and invisibility as well as in its motion. “Amber-colored amethyst” (line 3) acts as a colourful metaphor for the vœrtices at play within jellyfish, pitting yellow and purple, two colours that oppose each other on the colour wheel, against each other. Through these juxtapositions, the creature itself inhabits several vœrtices, placed within the point of tension between several opposing aesthetic variables: visible, invisible; orange, purple.
        This use of juxtaposing qualities is further used by Moore to describe the creature’s motion. The refrain of “It opens and it closes” (repeated with different punctuation and enjambment in lines 6-7 and 13-14) identifies the creature as permanently oscillating between two states of being.  While Moore does imply the presence of literal vœrtices within the poem, those created through the jellyfish’s motion through the water, the juxtaposition of opposites offers an excellent example of the ways creatures inhabit multiple less literal vœrtices by merely being.

The opposition between the jellyfish and the human character is centred around intent and desire. While the human desires “To catch it” (line 9), the jellyfish desires to evade, to “[float] away” (line 19).  These two impulses are equal, but opposite, and through their friction create a cognitive vœrtex between the two beings. 
        Returning to the notion of the jellyfish’s motion, the poem’s metrical pattern seems to replicate the even rhythm of the pulsing of a jellyfish’s bell as it swims by balancing stressed and unstressed syllables. Stressed syllables vary in placement between the first of every either two or four syllables. This metrical pattern seems at first to allow a rhythm that “fluctuat[es]” (line 2) with the jellyfish’s pace through the water. However, it’s important to note that these faster-paced moments may not always be produced by the jellyfish’s speed, but instead by the emotions of the human actor in the poem. The periods with stress every second syllable occur where there is an elevated sense of action, urgency, or desire. For example, the imagery within “An amber-colored amethyst” (line 3) evokes a sense of preciousness and rarity, which seems to inspire a strong desire to possess the creature within the human character of the poem, conveyed by the increase in stress from every fourth syllable to every second. However, it does not seem to refer to the jellyfish’s behaviour. This moment of desire is prior to any action by the human, and so warrants no reaction of a faster pace from the jellyfish. While the faster metre may overlap with the jellyfish’s pace of movement in moments of action and conflict, such as in “your arm / Approaches” (lines 4-5) and “You have meant / To catch it” (lines 8-9), it is not exclusive to it. This elevated pace may in fact also refer to the human actor’s heart rate as a result of the interaction between them and the jellyfish. This question of which entity’s experience is influencing the metre mirrors the vœrtex itself; both beings are locked in opposition, each battling to overpower the other. 

                  -      /
                The blue
                  -      /     -    -
                Surrounding it
                    -         /    -    -
                Grows cloudy, and
                 -    /     -   /
                It floats away
                     -       /
                From you. (lines 16-20)

        These final lines effectively superimpose the pace of the jellyfish’s movement upon the elevated emotional response within the human, ultimately establishing the two entities’ experiences as equal. The increased rate of rhythmic pulses seem to resemble both the speed of the jellyfish’s gentle escape, as well as the human’s elevated emotional response to their goal’s irretrievable distance. 
        Crucially, however, the vœrtex’s evanescence is not equal. The cognitive vœrtex between the human and jellyfish is dissolved when the jellyfish’s desire to escape successfully overpowers the human’s desire to catch it. The elevated emotional response within the human is a demonstration of the complex dynamic of attraction and rejection that often occurs in a vœrtex wake, the aftermath of a vœrtex’s evanescence. Given that in this situation, one force contributing to the vœrtex has overpowered the other, the wake of this vœrtex will result in an imbalance of attraction and repulsion, based on the momentum of each force. Since the cognitive opposition creating the vœrtex was already founded on the human’s attraction to the jellyfish, and the jellyfish’s repulsion to the human, the vœrtex wake continues along that same route as a lasting cognitive impression upon both parties. The human maintains an attraction to the jellyfish, but with the vœrtex’s dissolution the desire is transformed into an awareness of its absence. The jellyfish, however, maintains a repulsion from the human, with its desire to escape transformed into physical momentum. These are both evidenced in the last two lines of the poem; “It floats away / From you.”

Ultimately, the poem is an excellent example of the ways beings naturally inhabit multiple vœrtices, evidenced through Moore’s use of paradox and juxtaposition. Her use of metre also showcases the ways in which the tension of an interbeing vœrtex can be communicated and experienced, all the way through to the lasting effects and affects of the vœrtex wake.