Webster's Revised Unabridged Dictionary · 1913

Gymnosomata

Gymnosomata (jim"no*sō"mȧ*tȧ o jim"no*som"ȧ*tȧ) , noun, plural

[New Latin, from Greek gymno`s naked + sw^ma, sw`matos, the body.]

(Zoology) One of the orders of Pteropoda. They have no shell.