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TORSION Torsion is a process in which the viscero-pallium rotates anti-clockwise through 180° from its initial position during larval development. So that the mantle cavity, with its pallial complex, is brought to the front of the body in the adult. How Torsion Occurs Torsion is not an…
The “pearl” is literally formed by the mantle epithelium, which becomes deposit around any external body or particles, these external particle or body invade in between the shell and mantle in any way. Pearl is secreted by the mantle as a means of protection against a small external particle. When…
The pectoral girdle is connected to the vertebral column through muscles and ligaments. The pectoral girdle consists of two similar halves and each half is formed by three bones namely dorsal, ventral and antero ventral. The dorsal bone is known as scapula, the antero ventral bone is called clavicle and…
The skeletal system or skeleton includes the hard parts of the animal body. All the vertebrates possess the endoskeleton (inside the body). These are the living tissues develop from the interior layers of mesoderm of the body. The term skeleton denotes the endoskeleton in vertebrates. Skeleton plays a very important…
Comparative anatomy of respiratory systems in calotes (lizard), columba (pigeon) and oryctolagus (rabbit). Calotes is a poikilothermic terrestrial lizard. It is commonly known as garden lizard. Columba and oryctolagus are homoiothermic animals. Columba is commonly known as pigeon adapted for aerial mode of life. Oryctolagus is herbivorous mammal. It is…
Scoliodon (fish) is a poikilothermic cartilaginous fish. It is commonly known as shark. Rana (frog) is an amphibian and poikilothermic animal. It is commonly called as frog. Living cells require energy for performing metabolic activities. This energy is provided by the oxidation of food materials present within the cells.…
Digestive System Of Bird: Eg: Pegion Digestive System (Columba) Digestive System Of Mammal: Eg: Rabbit Digestive System (Oryctolagus) Digestive System Of Reptile: Eg: Lizard Digestive System (Calotes) In previous topic we discussed about the comparative anatomy of digestive system of frog and shark. In this topic we discussed about the…
Comparison Of Integument Derivatives In Calottes (Reptile), Columba (Bird) And Oryctolagus (Mammal) Calotes is a terrestrial Reptile (lizard). Columba is flying bird. Oryctolagus is a herbivorous mammal. All these animals are grouped under Amniota and columba & oryctolagus are warm blooded animals. The integument forms the outermost covering of the…
COMPARATIVE ACCOUNT OF THE INTEGUMENT (SKIN) IN THE SCOLIODON (SHARK FISH) AND RANA (FROG) Scoliodon and Rana are poikilothermic animals. Scoliodon is an aquatic cartilage fish. Rana lives in water and on land-amphibian. In both the vertebrates the skin (integument) is the outermost covering of the body. It is multicellular…
Herdmania is a bisexual animal. It is a protogynous animal. Ovary matures’ first. Hence cross fertilization takes place. Herdmania contains a pair of gonads. The left gonad lies in the intestinal loop above the heart. Each gonad shows 10 to 25 lobes arranged in two rows. The median lobe…
Herdmania is a hermaphrodite animal. The fertilised eggs undergo holoblastic unequal clevage and it develops into blastula. it shows upper micromeres and lower macromeres. By invagination of the macromeres gastrulation takes place and gastrula is formed. This gastrula develops into a tailed larva called Ascidian Tadpole larva. (Herdmanis life history,…
During metamorphosis the larva will loose all the chordate characters and attains an invertebrate like form. This type of metamorphosis, where highly advanced larval form ends in a lowly organised adult is called retrogressive metamorphosis. Fixation of the larva: The larva swims for some time without feeding. It is…
In the test of Herdmania two types of calcareous spicules are Present. They are: Microscleres: These are 40 to 80 microns in length. They are minute. Megascleres: These are long spicules. They show different shapes. They are 1.5 to 3.5 mm in length. They are two types.a) Spindle shaped…
A neural gland is present above the brain in herdmaina. It is brown in colour. It is present in the mantle. It is 4mm in diameter. It show branching tibuIes. At one end it leads into a short duct which opens by ciliated funnel above the dorsal tubercle. In the…
Herdmania shows brain or nerve ganglion. It is 4 mm long. It is present in the mantle in between the two siphons. A neural gland is present above the brain. From the brain three nerves arise, one goes to the bronchial siphon, and two will go to the atrial siphon.…
Herdmania is a simple ascidian, In Indian ocean this genus is represented by 4 species. 1. Herdmania pallida 2. H. ennurensis 3. H. mauritiana 4. H. ceylonica Herdmania belongs to, Phylum: Chordata Sub-phylum: Urochordata Class: Ascidiacea Order: Pleurogona Herdmania is a marine and sedentary animal. It…
