Petromyzon

Basis Overview of Petromyzon:  The most primitive Vertebrate are the jawless Vertebrate or Agnatha, both Ostracoderms and Cyclostomata belong to the group Agnatha. But Ostracoderms are extinct now so the Cyclostomata are the examples of living primitive Vertebrate. Petromyzon is jawless fish-like animals that live in both freshwater as well as marine water, the lamprey … Read more

Petromyzon is a fish-like aquatic animal, they spend most of the time in marine water but at a certain phase of time, they migrate in freshwater for reproduction. In the perspective of economic importance, the lamprey has a specific role in the food chain. In economics, the lamprey has both positive impacts as well as … Read more

Development in Petromyzon is indirect, their life cycle involves a certain larval stage after metamorphosis the larva convert into adult Petromyzon. Petromyzon is dioecious, male and female release gametes, in water fertilization occur externally. The female Petromyzon releases a large number of telolecithal eggs, but the eggs have a large quantity of yolk.  Then the … Read more

Nervous System of Petromyzon:  In Petromyzon, the nervous system has a very primitive brain, the main region of the brain, cerebral hemispheres are two in number and they are much separated from each other. The forebrain has two large olfactory lobes, on the posterior region, the cerebral hemispheres are connected to the diencephalon, on the … Read more

Respiratory System of Petromyzon:  On the lateral side of the head, seven pairs of gill slits are present, the gills are present inside the gill pouches. Between the respiratory pharynx and the body wall the gill pouches present, on external appearance, each gill pouch looks like a biconvex lens. The gill pouches are separate from … Read more

Digestive System of Petromyzon:  Buccal Cavity and Mouth:  Petromyzon has a complete digestive system with the alimentary canal starting at the mouth and ending at the anus, the mouth present on the ventral side of the anterior part of the cylindrical head. Petromyzon feed on other fishes, their mouth show adaptation for parasitism. The ventral … Read more

Anatomy of Skin:  The skin has muti layered cells coverings, have dermis and epidermis layers, the skin is slimy or smooth due to the presence of mucous gland. The epidermis has different types of cells, the major type of cells present on the epidermis is mucous gland secret mucous, other glandular cells present on the … Read more

Body Shape of Petromyzon:  Petromyzon or Lamprey are fish-like animals in external appearance, specially Petromyzon are resemblance less or more with eels. The body is divided into three parts, the anterior cylindrical-shaped head, then the large-sized cylindrical trunk portion, and the posterior post-anal tail. The tail is laterally compressed, the head-tail and trunk are not … Read more