Etymology of "urchin"

[wevets]

“Please sir, can I have some more?”

“Ow! Get away from me, rapscallion, you’re all pokey!”

At least, I’m assuming Dickens didn’t write about youth sporting spikes (imagine if he had - Dickensian Punk!), tube feet, and an Aristotle’s Lantern.

So why are street urchins and sea urchins called the same thing? I get the Hedgehog-Sea Urchin connection from Merriam-Webster, but why street urchins?
Bonus points to anyone who can use “Aristotle’s Lantern” in a pun.

[Exapno_Mapcase]

For one stop etymology, try the Online Etymology Dictionary

urchin
c.1290 yrichon “hedgehog,” from O.N.Fr. *irechon (cf. Picard irechon, Walloon ireson, Hainaut hirchon), from O.Fr. herichun “hedgehog” (Fr. hérisson), formed with dim. suffix -on from V.L. *hericionem, from L. ericius “hedgehog,” from PIE base *gher- “to bristle” (cf. Gk. kheros “hedgehog;” see horror). Still used for “hedgehog” in non-standard speech in Cumbria, Yorkshire, Shropshire. Applied throughout 16c. to people whose appearance or behavior suggested hedgehogs, from hunchbacks (1528) to goblins (1584) to bad girls (c.1530); meaning “poorly or raggedly clothed youngster” emerged 1556, but was not in frequent use until after c.1780. Sea urchin is recorded from 1591 (a 19c. Newfoundland name for them was whore’s eggs).