Orders: Stegocephalia, A poda (or Peromela), Caudata (or Urodela), Ecaudata (or Anura).
A bird called moho, but actually of a different family, was the Pennula ecaudata or millsi, which had hardly any tail, and had wings so degenerate that it was commonly thought wingless.
FROG, 1 a name in zoology, of somewhat wide application, strictly for an animal belonging to the family Ranidae, but also used of some other families of the order Ecaudata of the sub-class Batrachia.
The genus Rana may be defined as firmisternal Ecaudata with cylindrical transverse processes to the sacral vertebra, teeth in the upper jaw and on the vomer, a protrusible tongue which is free and forked behind, a horizontal pupil and more or less webbed toes.
Owen, which name is restricted to the forms for which it was originally intended; Peromela, Urodela, Anura, are changed to Apoda, Caudata, Ecaudata, for the reason that (unless obviously misleading, which is not the case in the present instance) the first proposed name should supersede all others for higher groups as well as for genera and species, and the latter set have the benefit of the law of priority.
p. 72), added the Caecilians, he named the three groups Apoda, Ecaudata and Caudata.
The Discoglossidae are noteworthy for the presence of short ribs to some of the vertebrae, and in some other points also they approach the tailed batrachians; they may be safely regarded as, on the whole, the most generalized of known Ecaudata.
According to our present knowledge, the Ecaudata can be traced about as far back in time as the Caudata.
In the Ecaudata, the vertebrae of the trunk are formed on two different plans.
Amphicoelous (bi-concave) vertebrae are found in the Apoda and in some of the Caudata; opisthocoelous (convexo-concave) vertebrae in the higher Caudata and in the lower Ecaudata; whilst the great majority of the Ecaudata have procoelous (concavo-convex) vertebrae.
Ribs are present in the lower Ecaudata (Discoglos- sidae and larval R.0- but they are never connected with a sternum.
In the Ecaudata, the form of the transverse processes of the sacral vertebra varies very considerably, and has afforded important characters to the systematist.
In the Caudata, the frontals remain likewise distinct from the parietals, whilst in the Ecaudata the two elements are fused into one, and in a few forms (Aglossa, some Pelobatidae) the paired condition of these bones has disappeared in the adult.
Prefrontal bones are present in the Salamandridae and Amphiumidae, but absent (or fused with the nasals) in the other Caudata and in the Ecaudata.
In the lower jaw of most of the Ecaudata the symphysial cartilages ossify separately from the dentary bones, forming the so-called mento-meckelian bones; but these symphysial bones, so distinct in the frog, are less so in the Hylidae and Bufonidae, almost indistinguishable in the Pelobatidae and Discoglossidae, whilst in the Aglossa they do not exist any more than in the other orders of batrachians.
In the Ecaudata, as shown by E.
z '` common among the salamanders, is unique among the Ecaudata (31).
In most of the Caudata the scapular region alone ossifies, but in the Ecaudata the coracoid is bony and a clavicle is frequently developed over the praecoracoid car tilage.
The former type is exemplified by the toads and the lower Ecaudata, whilst the latter is characteristic of the true frogs (Ranidae), although when quite young these batrachians present a condition similar to that which persists throughout life in their lower relatives.
In the Ecaudata the ilium is greatly elongated and the pubis and ischium are flattened, discoidal, and closely applied to their fellows by their inner surfaces; the pelvic girdle looks like a pair of tongs.
In the Ecaudata the radius and ulna coalesce into one bone.
Except in some of the Stegocephalia, there are only four functional digits in the manus, but the Ecaudata have a more or less distinct rudiment of pollex; in the Caudata it seems to be the outer digit which has been suppresssed, as atavistic reappearance of a fifth digit takes place on the outer side of the manus, as it does on the pes in those forms in which the toes are reduced to four.
The usual number of phalanges is 2, 2, 3, 2 in the Stegocephalia and Caudata, 2, 2, 3, 3 in the Ecaudata.
In the foot the digits usually number five, and the phalanges 2, 2, 3, 3, 2 in the Caudata, 2, 2, 3, 4, 3 in the Stegocephalia and Ecaudata.
There are usually nine tarsal elements in the Caudata; this number is reduced in the Ecaudata, in which the two bones of the proximal row (sometimes coalesced) are much elongated and form an additional segment to the greatly lengthened hind-limb, a sort of crus secundarium.
In the Ecaudata also, the tibia and fibula coalesce into one bone, and two or three small bones on the inner side of the tarsus form what has been regarded as a rudimentary digit or "prehallux."
m In all larval forms, in the Caudata, and in a few of the Ecaudata (Xenopus, for instance), the epidermis becomes modified in relation with the termination of sensory nerves, and gives rise to organs of the same nature as those of the lateral line of fishes.
they are nearly always absent in the lower Br', Br 2, Br a, Branjaw of the Ecaudata (exceptions in Hemi- chial arches.
But the larvae of the Ecaudata are mainly herbivorous and the digestive tract is accordingly extremely elongate and coiled up like the spring of a watch.
The tongue is rudimentary in the perennibranchiate Caudata, well developed, and often protrusile, in the Salamandridae and most of the Ecaudata, totally absent in the Aglossa.
Howes (39), dealing with the azygous (posterior) cardinal veins in salamanders and some of the Ecaudata.
The larynx, which is rudimentary in most of the Caudata and in the Apoda, is highly developed in the Ecaudata, and becomes the instrument of the powerful voice with which many of the frogs and toads are provided.
The lungs are long simple tubes in some of the perennibranchiate Caudata; they generally shorten or become cellular in the salamandrids, and attain their highest development in the Ecaudata, especially in such forms as the burrowing Pelobates.
Many of the Ecaudata have remnants of oviducts, or Miillerian ducts, most developed in Bufo, which genus is also remarkable as possessing a problematic organ, Bidder's organ, situated between the testis and the adipose or fat-bodies that surmount it.
The first category embraces many aquatic newts, the second nearly all the Ecaudata, the third the rest of the Caudata, and the fourth the Apoda.
The eggs are also deposited singly in some of the lower Ecaudata.
In many of the Ecaudata, and in a few of the Caudata and Apoda, the eggs are laid in strings or bands which are twined round aquatic plants or carried by the parent; whilst in other Ecaudata they form large masses which either float on the surface of the water or sink to the bottom.
In the Caudata, external gills (three on each side) persist until the close of the metamorphosis, whilst in the Apoda and Ecaudata they exist only during the earlier periods, being afterwards replaced by internal gills.
The first would be characterized by the Caudata, which are almost confined to it (although a few species penetrate into the Indian and neotropical regions), the Discoglossidae, mostly Europaeo-Asiatic, but one genus in California, and the numerous Pelobatidae; the second by the presence of Apoda, the prevalence of firmisternal Ecaudata and the absence of Hylidae; the third by the presence of Apoda, the prevalence of arciferous Ecaudata and the scarcity of Ranidae, the fourth by the prevalence of arciferous Ecaudata and the absence of Ranidae, as well as b y the absence of either Caudata or Apoda.
Madagascar might almost stand as a fifth division of the world, characterized by the total absence of Caudata, Apoda, and arciferous Ecaudata.
It may be noted here that no two parts of the world differ so considerably in their Ecaudata as do Madagascar and Australia, the former having only Firmisternia, the latter only Arcifera.
Ecaudata in the Collection of the British Museum (London, 1882, 8vo).
They are less marked or more gradual in the Apoda and Caudata than in Ecaudata, in which the stage known as tadpole is very unlike the frog or toad into which it rather suddenly passes (see Tadpole).
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.