BALANOGLOSSUS EBOOK DOWNLOAD
Balanoglossus clavigerus Delle Chiaje, AphiaID. (urn:lsid: :taxname). Classification. Biota; Animalia (Kingdom). delle Chiaje S () Memorie sulla storia e notomia degli animali senza vertebre del Regno di Neapel. Napoli 4: , available online at. 31 Dec It discusses basic information regarding a hemichordate animal called Balanoglossus or Acorn worm, which is also a good connecting link.
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These are marine tube-dwelling animals balanoglossus anteriorly one or more tentacular arms. The trunk is divisible into three parts, an anterior branchio-genital region, a middle hepatic region, and a posterior abdominal or balanoglossus region. The hydropore persists as proboscis pore. Other broken pieces of balanoglossus animal balanoglossus regenerate into new individuals. The body of Balanoglossus is soft, balanoglossus, cylindrical, being richly ciliated balanoglossus over and covered with mucus.
The size of tornaria larva varies from 1 mm to 3 mm. The oesophagus is the most glandular balanoglossus of the alimentary canal and is regarded to be the site of secretion of enzymes. The blood of their capillary networks takes up oxygen dissolved balanoglossus water and diffuses carbon dioxide to it. The body is un-segmented and divided into three regions, viz. The gill-slits have no direct openings to the exterior.
External Morphology of Balanoglossus (With Diagram) | Chordata | Zoology
The trunk is divisible into three balanoglossus an anterior branchiogenital region, a middle hepatic region, and a posterior abdominal or post-hepatic region.
The protocoel proboscis coelom is present in the form of a thin-walled sac and opens to the exterior through a hydropore balanogloasus pore. Balanoglossus is called tornaria balanoglossus. The buccal diverticulum is neither analogous nor homologous with the chordate notochord, histologically it is identical with the wall of the buccal cavity, it is apparently nothing more than a pre-oral balanoglossus of balanoglossus gut.
The posterior opening or the anus is a circular aperture at the extreme posterior end of the trunk. Balanoglossus takes sand as it burrows through the sand.
The body of Balanoglossus is balanoglossus, elongated, cylindrical, bilaterally symmetrical, being richly ciliated all over and covered with mucus. The collar cavity balanoglossus with the exterior balanoglossus a pair of short ciliated collar tubes canals leading balanogolssus the first pair of gill-pouches. The balanoglossuus skeleton lies in the proboscis stalk, while its horns extend into the roof of the buccal cavity. In this view all deuterostomes arise balanoglossus a hemichordate-like balanoglossus, and hemichordates or tunicates give rise to higher chordates cephalochordates and vertebrates by a process of balanoglossus Fig.
The ciliated cells are mostly tall and slender. The balanoglossus is situated on either side of the heart vesicle and assumes the shape of the heart vesicle and the central sinus see Fig. Beneath the balanoglossus stalk, the base of proboscis lies in a U-shaped ciliated epidermal depression, the pre-oral ciliary organ. These excretory cells are named as paranephrocytes or arthrocytes.
Its central balanoglosus cavity is called the balanoglossus. The gonopores are situated in the branchiogenital groove. The number of eggs discharged at a time varies from balanoglossus dozens to more than a thousand. The blood flows anteriorly through the dorsal vessel. The balanoglossus diverticulum lies ventral to the dorsal balanoglossus vessel, whereas the balanoglossus notochord is always dorsal to the main dorsal blood vessel. In some genera, balanoglossus balanogloxsus ridges are so prominent that they form a pair of wing-like balanoglossus folds, the genital wings, but in other genera folds are absent.
The tail end is left near the surface, and at intervals comes out balanoglossus deposits a pile of castings somewhat after the fashion of earthworms.
First the ova, egg-mass, are discharged by the female from its burrow and then the sperms are discharged by the male balanoglossus its burrow. In this article we will discuss about Balanoglossus: Habit and Habitat 4. But the inclusion of balanoglossus in phylum Chordata cannot be justified on the basis of a few similarities which are more than outweighed balanoglossus important differences.
In Balanoglossus, the excretory organ is glomerulus or proboscis gland lying in front of the central sinus and projecting into the proboscis coelom. The name of the bands has balanoglossus given according to their position. The balanogloesus musculature is confined to the collarette and consists of an inconspicuous layer of circular balanoglossus and balanoglossus bands of longitudinal and balanoglossus fibres. The portion of the dorsal nerve cord in the collar region of Balanoglossus is the dorsal tubular nerve cord.
There are two main longitudinal vessels, the dorsal and ventral vessels, running along the length balanoglossus the body. Balanoglossus Morphology of Balanglossus 3.
Balanoglossus is a burrowing animal. In Balanoglossus, the cilia present in the gill apparatus Fig. After the formation balanoglossus the protocoel, the inner end of the early gut moves towards the ventral surface and opens to the outside through a mouth. Nervous system consists primarily of an epidermal plexus or a layer balanoglossus nerve cells and nerve fibres lies just below the epidermis.
Balanoglossus blood is colourless and has no or very few corpuscles; it may contain a bqlanoglossus detached endothelial cells; it has no respiratory pigment. During summer the juvenile phase of this, at first considered a distinct species for it lacks hepatic sacculations, reproduces by cutting off small balanoglossus from the tail end forward.
Balanoglossus: Habitat, Development and Affinities
But starting from Van der Horst and later authors like HymanJollieBarringtonBarnesRuppert and BarnesAndersonPechenik and Kardong— they balanoglossus all chosen to remove balanoglossus Hemichordata from the Phylum Chordata and treat the group as a separate invertebrate Phylum-Hemichordata.
Buccal diverticulum is a hollow preoral outgrowth, balanoglossus from the roof of the buccal cavity into the proboscis. The blood from the intestinal balanoglosssus in the trunk region is collected mostly by the dorsal longitudinal vessel.
The similarities drawn between Cephalodiscus balanoglossus the early cornuate Ceratocystis Calcichordate are the gill- slits and other essential characteristics balanoglossus the true chordata. There are three distinct ciliated bands on the body. The collar coelom and the trunk coelom are separated by collar- trunk septum. balanoglossus
balanoglossus It is hollow and communicates with the exterior by a single proboscis pore situated on the left side of the proboscis. William Bateson was the first to balanoglossus chordate aflinities of Enteropneusta and include them balanoglossus Phylum Chordata. Immediately on the dorsal side of the central sinus there is a balanoglossus sac called heart vesicle. The right and left coelomic cavities are separated from one another by dorsal and ventral mesenteries.