Juergen Freund / Eggcase of Swell shark showing embryo. (C. ventriosum) Pacific Cephaloscyllium

Flip Nicklin / Swell Shark (Cephaloscyllium ventriosum) egg case with embryo, sometimes called mermaid's purses, the pups will hatch in 7-10 months, native to the Pacific Ocean

Norbert Wu / Swell Shark (Cephaloscyllium ventriosum) swells up as defense, California

Norbert Wu / Swell Shark (Cephaloscyllium ventriosum) underwater, so named because it swells up as defense against predators, California

Flip Nicklin / Swell Shark (Cephaloscyllium ventriosum) eye

Flip Nicklin / Swell Shark (Cephaloscyllium ventriosum) close-up of teeth

Flip Nicklin / Swell Shark (Cephaloscyllium ventriosum) close-up of face

Flip Nicklin / Swell Shark (Cephaloscyllium ventriosum) pair

Flip Nicklin / Swell Shark (Cephaloscyllium ventriosum) egg cases with embryos, sometimes called mermaid's purses, the pups will hatch in 7-10 months

Flip Nicklin / Swell Shark (Cephaloscyllium ventriosum) egg cases with embryos, sometimes called mermaid's purses, the pups will hatch in 7-10 months

Jeff Rotman / Rows of replaceable teeth of the swell shark. (C ventriosum) USA California

Juergen Freund / Eggcase of swell shark (Cephaloscyllum ventriosum) showing embryo, Pacific Ocean

Juergen Freund / Close up of egg-case of Swell shark showing embryo, Pacific Ocean

Juergen Freund / Egg-case of Swell shark amongst coral, Pacific Ocean

Jeff Rotman / Claspers of male Swell shark {Cephaloscyllium ventriosum} California USA