It is still more remarkable than the amphioxus or lancelet, which has been long known.
By "launces" the writer meant what we should now call the lancelet.
The lancelet also differs from the true vertebrates, in that it has no limbs.
The lowest of the Vertebrata, the lancelet (see p. 140), has a larva of this kind.
The spleen, a dark-red lymphatic gland, is found attached to the stomach in all fish-like vertebrates except the lancelet.
This gap was filled some years ago by the discovery of the lancelet—Amphioxus—and the young of the sea-squirt—Ascidia.
There is a huge gap between the lancelet and the true vertebrates.
The development of the lancelet presents us with an instance of the two-layered larva, or Gastrula.
The liver in the lancelet is a long diverticulum of the intestine.
From the lowest of the Vertebrata, the lancelet, we passed on to the Lamprey, and from that to the true fishes.
Any of various small, transparent, fishlike marine organisms of the subphylum Cephalochordata that are related to vertebrates but have a notochord instead of a true backbone. Unlike other primitive chordates, lancelets have a body divided into serially repeated muscular segments. Also called amphioxus.