Remember that jellyfish constitute an entire phylum, on the same level as chordata. - all creatures with a notochord.
Alternatively, are you trying to define 'kind' as an entire phylum. That would certainly reduce crowding on Noah's ark.
Jellyfish are in the phylum cnidaria,which is comprised of thousands of families and genera.
The Cnidaria (pronounced nidaria)as a group of animals are well known to many people under their common names, Sea Anemones, Corals and Jellyfish are all Cnidarians as are Hydras, Sea Whips, Sea Fans and Sea Pansies. They are linked together by their carnivorous feeding habits their simple anatomical design and the possession of nematocysts, though one species of Ctenophora possesses nematocysts as well.
The name Cnidaria has now pretty much replaced the older term of Coelenterata (pronounced selenterata) which these days is often applied to both the Cnidaria and the Ctenophora together, these two phyla are also known as the Radiate Animals because they both have radial or biradial symmetry. The word Cnidaria refers to Cnidocysts, specialised cells which contain the Nematocysts, the stinging organelles that allow the Cnidaria to subdue their prey.
The Cnidaria are the oldest of the true metazoan phyla. A fossil Hydrozoan from South Australia called Ediacara is 700 million years old, while numerous fossil Cnidarians exist from the Cambrian 500 million years ago. The Cnidarians, particularly the corals often make up an important component of the shallow marine fauna of tropical and subtropical seas. All the Cnidaria are aquatic and nearly all are marine. Corals because of their shallow marine environment and their habit of accumulating a mineralised skeleton (coralite) tend to fossilize well and we know quite a bit about their evolution.
The Cnidarian body is basically a U shape with intact walls that surround a central digestive area and a mouth at the opening, generally surrounded by tentacles, there is no distinct anus. In Anemones the mouth faces up, and in Jellyfish it faces down. The Cnidarians show a more complicated arrangement of cell layers as well as a greater range of cell types than the Porifera. Their bodies show two distinct layers of cells and thus they are called 'Diploblastic animals'. The two cell layers are an outer Epidermis or Ectoderm, and an inner Gastrodermis or Endoderm. These two layers are separated by the mesoglea a non-cellular fibrous jelly like material that is thin in some groups such as the Hydras but can be quite thick in other such as the Jellyfish where it helps provide negative buoyancy (makes the animal more likely to float). The ectodermis consists of five basic cell types, Epitheliomuscular cells which supply some of the muscular capabilities of the animal, Interstitial cells which are basic cells that give rise to the other cell types, Cnidocysts (see below), Mucous glands and sensory or nerve cells. The endodermis consists of three or four basic cell types Gastromuscular cells which help digest food items and provide some muscle power, Gland cells that secrete enzymes for digestion, Mucous cells and in Anemones but not in Hydras, Cnidocytes.
One of the most important distinguishing characteristics of the phylum are the Nematocysts. Nematocysts, and their enclosing Cnidocysts come in about 24 different forms, the differences play a functional role in the classification of the phylum. A Cnidocyst is a cell that secretes a nematocyst within it. A basic Nematocyst is a capsule made of something like chitin within which rest a coiled thread. This thread can be shot out of the capsule to encounter prey items, or in some cases to repel predators. The Cnidocyst has either a modified flagellum called a Cnidocil, or a cone as a sensory trigger. If this trigger is touched the nematocyst thread is rapidly ejected. Nematocyst threads come in 3 basic types. The fundamental nematocyst is a thin tubular thread with barbs at the far end, though there may be barbs near the base as well. When the nematocyst is discharged, the barbs penetrate the skin of the prey and a toxin can be injected. Ptychocysts are uncommon, occurring only in the Ceriantharians, they lack spines or barbs but are adhesive and can be used to line the tubes the Ceriantharians live in as well as to entangle prey. Spirocysts also lack barbs or spines, they are an enclosed tube that is adhesive, they are used to trap prey in a tangled net of sticky threads.
I think your using this mischaracterization to imply that Creationists believe evolution occurs at the phylum level.
There is no demonstratable or experimental evidence that evolution can cross the species or genus level.