Vertebrata Sentence Examples
The parasitic Nematodes include by far the greatest number of the known genera; they are found in nearly all the orders of the animal kingdom, but more especially among the Vertebrata, and of these the Mammalia are infested by a greater variety than any of the other groups.
Notwithstanding the origin of organs, it still for a certain time, by reason of its want of an internal bony skeleton, remains worm and mollusk, and only later enters into the series of the Vertebrata, although traces of the vertebral column even in the earliest periods testify its claim to a place in that series."
The Vertebrata come within the scope of our subject, chiefly as destructive agents which cause wounds or devour young shoots and foliage, &c. Rabbits and other burrowing animals injure roots, squirrels and birds snip off buds, horned cattle strip off bark, and so forth.
Thus in the Chaetopoda the perivisceral cavity is coelomic; in this respect the group contrasts with the Arthropoda and Molluscs, where the perivisceral cavity is, mainly at least, part of the vascular or haemal system, and agrees with the Vertebrata.
This state of affairs has no antecedent improbability about it, since in the Vertebrata the coelom is unquestionably confluent with the haemal system through the lymphatic vessels.
Thus the postcaval vein of the higher vertebrata is partly a new structure altogether, and is partly formed out of the pre-existing posterior cardinals.
Sutures are stated to mark off some of these pieces, but in the proper sense of that term as applied to the skeletal structures of the Vertebrata, no sutures exist in the chitinous cuticle of Arthropods.
That any partial fusion of originally distinct chitinous plates takes place in the cephalic shield of Trilobites, comparable to the partial fusion of bony pieces by suture in Vertebrata, is a suggestion contrary to fact.
Latreille 6 published a new classification of the Vertebrata, which are primarily divided into Haematherma, containing the three classes of Maminifera, Monotremata and A y es; and Haemacryma, also containing three classes - Reptilia, Amphibia and Pisces.
This division of the Vertebrata into hot and cold blooded is a curiously retrograde step, only intelligible when we reflect that the excellent entomologist had no real comprehension of vertebrate morphology; but he makes some atonement for the blunder by steadily upholding the class distinctness of the Amphibia.
AdvertisementHuxley adopted Latreille's view of the distinctness of the Amphibia, as a class of the Vertebrata, co-ordinate with the Mammalia, A y es, Reptilia and Pisces; and the same arrangement was accepted by Gegenbaur and Haeckel.
In the Hunterian lectures delivered at the Royal College of Surgeons in 1863, Huxley divided the Vertebrata into Mammals, Sauroids and Ichthyoids, the latter division containing the Amphibia and Pisces.
Sir Richard Owen, in his work on The Anatomy of Vertebrates, followed Latreille in dividing the Vertebrata into Haematotherma and Haematocrya, and adopted Leuckart's term of Dipnoa for the Amphibia.
The phosphate beds contain Eocene fossils derived from the underlying strata and many fragments of Pleistocene vertebrata such as mastodon, elephant, stag, horse, pig, &c. The phosphate occurs as lumps varying greatly in size, scattered through a sand or clay; they often contain phosphatized Eocene fossils (Mollusca, &c.).
It is now applied throughout the Vertebrata of both Mesozoic and Cenozoic times.
AdvertisementIt must, however, be distinctly borne in mind that there is a fundamental difference between the eye of Vertebrates and of all other groups in the fact that in the Vertebrata the retinal body is itself a part of the central nervous system, and not a separate C E k e FIG.
In 1866 the Russian embryologist Kowalewsky startled the zoological world with a minute account of the developmental changes of Ascidia, one of the Tunicata, 5 and it became evident that the affinities of that class were with the Vertebrata, whilst their structural agreements with Mollusca were only superficial.
The Mollusca agree in being coelomate with the phyla Vertebrata, Platyhelmia (flat-worms), Echinoderma, Appendiculata (insects, ringed-worms, &c.), and others - in fact, with all the Metazoa except the sponges, corals, polyps, and medusae.
The most that can be said is that the Chaetognaths begin life with three segments, a feature they share with such widelydiffering groups as the Brachiopoda, the Echinoderma and the Enteropneusta, and probably Vertebrata generally.
One result of this among the Vertebrata is that the eyeball is pink in colour, since the cornea, iris and retina being transparent, the red blood contained in the capillaries is unmasked by the absence of pigmentary material.
AdvertisementThe remaining classes of Vertebrata are very sparsely represented in the high Alps; and what few species occur are mostly common to the plains as well.
The broader theories of modern zoology might seem to have little bearing on the Echinoderma, for it is not long since the study of these animals was compared to a landlocked sea undisturbed by such storms as rage around the origin of the Vertebrata.
Although the present article does not discuss mammalian osteology in general (for which see Vertebrata), it is interesting to notice in this connexion that the primitive condition of the mammalian tympanum apparently consisted merely of a small and incomplete bony ring, with, at most, an imperfect ventral wall to the tympanic cavity, and that a close approximation to this original condition still persists in the monotremes, especially Ornithorhynchus.
A similar constitution of the body is more clearly seen in the Chaetopod worms. In the Vertebrata also a repetition of units of structure (myotomes, vertebrae, &c.) - which is essentially of the same nature as the repetition in Arthropods and Chaetopods, but in many respects subject to peculiar developments - is observed.