By some writers the branchiopods, the bryzoans, and the tunicates are also included.
Defn: A genus of transparent, tubular, free-swimming oceanic tunicates found abundantly in all the warmer latitudes.
Some live in the cavities of tunicates or sponges or holothurians or corals or oysters, often passing their whole lives inside the cavity of one animal.
This definition excludes the Tunicates and Enteropneusta on the one hand and the Amphibia or Batrachia with the reptiles, birds, and mammals on the other.
There are numerous families of Tunicatesand the species are found in nearly all seas.
The Ascidiidae comprise the most familiar solitary forms, some of them the largest of the Tunicates and represented on most coasts.
The Tunicatesare all marine, some floating or swimming freely, some attached to rocks or wharves, others buried in the sand.
Unlike the Tunicates it represents a primitively simple, not a degenerate, type.
For the changes suggested I am indebted to the kindness of Professor William Emerson Ritter: The Tunicates derive their name from the fact that the whole body is invested with a tough envelope or "tunic.
No fossil Tunicates are known, as they possess no hard parts, although certain Ostracoderms have been suspected, though on very uncertain grounds, to be mailed Tunicates, rather than mailed lampreys.
In the order Thaliacea the Tunicates have the two orifices at opposite ends of the body.
Ritter writes: "In addition to the sexual method of reproduction, many tunicates reproduce asexually by budding.
A genus of transparent, tubular, free-swimming oceanic tunicates found abundantly in all the warmer latitudes.
The enigmatic neurenteric canal is a very old embryonic organ, and of great phylogenetic interest, because it arises in the same way in all the chordonia (both tunicates and vertebrates).
Hence we may conclude, according to the laws of the theory of descent, that all these chordonia or chordata (tunicates and vertebrates) descend from an ancient common ancestral form, which we may call Chordaea.
I ascribe the utmost phylogenetic significance to it, as it is found in all the chorda-animals (tunicates as well as vertebrates) in essentially the same form.
The tunicates are by some authors classed with the vertebrate animals because in the larval stage they have a notochord; this disappears, however, in the adult form, and the animals are considered degenerates.
The tunicates are interesting to biologists from the remarkable changes they undergo in their life-history, and (in some genera) the marked phase of alternation of generation.
The tunicates are widely distributed, and occur at all depths.
These instructive Copelata, comparable to permanent Ascidia-larvae, come next to the extinct Prochordonia, those ancient worms which we must regard as the common ancestors of the Tunicates and Vertebrates.
When we turn from the Tunicates to the closely-related Amphioxus we are astonished at first to find an apparent retrogression in the formation of the vascular system.
The differentiation of these two parts of the gut in the Enteropneust is just the same as in all the Tunicates and Vertebrates.
Undoubtedly both the Tunicatesand Acrania have inherited the chorda from a common unsegmented stem-form; and these ancient, long-extinct ancestors of all the chordonia are our hypothetical Prochordonia.
As both the Tunicatesand the Vertebrates develop from the same chordula, we may infer that there was a corresponding common ancestor of both stems.
The tunicates are the only class of animals that have a real cellulose or woody coat.
The discovery was confirmed by other zoologists, and there can no longer be any doubt that of all the classes of invertebrates that of the Tunicates is most closely related to the vertebrates, and of the Tunicates the nearest are the Ascidiae.
It has descended from the Cyclostoma by a profound degeneration, and these in turn from the fishes; even the Ascidia and the whole of the Tunicatesare merely degenerate fishes!
The vertebrates and the closely related tunicates are distinguished by the conversion of the first sections of the alimentary canal into a characteristic respiratory apparatus (gills).
The heart is formed from the dorsal vessel in the mollusks and articulates, but from the ventral in the tunicates and vertebrates.
In the tunicates (salpa) a sexual social form alternates with an asexual solitary form; the chain-salpa of the former are smaller and differently shaped than the large individual salpa of the latter, which again generate chains by budding.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "tunicates" in a variety of sentences. We hope that you will now be able to make sentences using this word.
