In this article we will discuss about Dipnoi:- 1. Introduction to Dipnoi 2. Geographical Distribution of Dipnoi 3. Palaeozoic Records 4. Habit and Habitat 5. External Structures 6. Skeletal Structures 7. Digestive System 8. Respiratory System 9. Circulatory System 10. Nervous System 11. Endocrine System 12. Excretory System 13. Reproductive System 14. Affinities 15. Cytogenetic Evidence. Contents: Introduction to Dipnoi [...]
The below mentioned article provides a note on the evolution and classification of fishes. Fishes are generally grouped into three broad categories: the placoderms, the cartilaginous fishes and the bony fishes. The placoderms include the primitive and extinct fishes, the cartilaginous fishes comprise the elasmobranchs and the holocephali, while the bony fishes include the Actinopterygians, Crossopterygians and Dipnoans. Each of [...]
The following points highlight the four main sense organs in fishes. The sense organs are: 1. Eye 2. Ear 3. Lateral-Line System 4. Hoagland. Sense Organ # 1. Eye: The eyes of fishes are the photoreceptors to see things under water. The eyes are typically built on the principle of a photographic camera. The eye ball is composed of three [...]